description: Theofanis has a string s_1 s_2 ... s_n and a character c. He wants to make all characters of the string equal to c using the minimum number of operations.
  
  In one operation he can choose a number x (1 ≤ x ≤ n) and for every position i, where i is not divisible by x, replace s_i with c. 
  
  Find the minimum number of operations required to make all the characters equal to c and the x-s that he should use in his operations.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases.
  
  The first line of each test case contains the integer n (3 ≤ n ≤ 3 ⋅ 10^5) and a lowercase Latin letter c — the length of the string s and the character the resulting string should consist of.
  
  The second line of each test case contains a string s of lowercase Latin letters — the initial string.
  
  It is guaranteed that the sum of n over all test cases does not exceed 3 ⋅ 10^5.
  
  Output
  
  For each test case, firstly print one integer m — the minimum number of operations required to make all the characters equal to c.
  
  Next, print m integers x_1, x_2, ..., x_m (1 ≤ x_j ≤ n) — the x-s that should be used in the order they are given.
  
  It can be proved that under given constraints, an answer always exists. If there are multiple answers, print any.
  
  Example
  
  Input
  
  
  3
  4 a
  aaaa
  4 a
  baaa
  4 b
  bzyx
  
  
  Output
  
  
  0
  1
  2
  2 
  2 3
  
  Note
  
  Let's describe what happens in the third test case: 
  
    1. x_1 = 2: we choose all positions that are not divisible by 2 and replace them, i. e. bzyx → bzbx; 
    2. x_2 = 3: we choose all positions that are not divisible by 3 and replace them, i. e. bzbx → bbbb. 
solution: 
  import java.util.*;
  import java.util.concurrent.CompletableFuture;
  
  import javax.swing.event.TreeExpansionEvent;
  import javax.swing.text.Segment;
  
  
  import java.io.*;
  import java.math.*;
  import java.sql.Array;
  
  
  
  public class Main {
  	  static class Reader{
  		  
  			BufferedReader br;
  			StringTokenizer st;
  			public Reader() {
  				br = new BufferedReader(new InputStreamReader(System.in));
  			}
  			String next() 
  		    { 
  		        while (st == null || !st.hasMoreElements()) 
  		        { 
  		            try
  		            { 
  		                st = new StringTokenizer(br.readLine()); 
  		            } 
  		            catch (IOException  e) 
  		            { 
  		                e.printStackTrace(); 
  		            } 
  		        } 
  		        return st.nextToken(); 
  		    } 
  
  		    int nextInt() 
  		    { 
  		        return Integer.parseInt(next()); 
  		    } 
  
  		    long nextLong() 
  		    { 
  		        return Long.parseLong(next()); 
  		    } 
  
  		    double nextDouble() 
  		    { 
  		        return Double.parseDouble(next()); 
  		    } 
  
  		    String nextLine() 
  		    { 
  		        String str = ""; 
  		        try
  		        { 
  		            str = br.readLine(); 
  		        } 
  		        catch (IOException e) 
  		        { 
  		            e.printStackTrace(); 
  		        } 
  		        return str; 
  		    } 
  		}
  	 
  	  static long mod = (long)(1e9 + 7);
  	 
  	static void sort(long[] arr ) {
  		 ArrayList<Long> al = new ArrayList<>();
  		 for(long e:arr) al.add(e);
  		 Collections.sort(al);
  		 for(int i = 0 ; i<al.size(); i++) arr[i] = al.get(i);
  	 }
  	static void sort(int[] arr ) {
  		 ArrayList<Integer> al = new ArrayList<>();
  		 for(int e:arr) al.add(e);
  		 Collections.sort(al);
  		 for(int i = 0 ; i<al.size(); i++) arr[i] = al.get(i);
  	 }
  	static void sort(char[] arr) {
  		ArrayList<Character> al = new ArrayList<Character>();
  		for(char cc:arr) al.add(cc);
  		Collections.sort(al);
  		for(int i = 0 ;i<arr.length ;i++) arr[i] = al.get(i);
  	}
  	static void rvrs(int[] arr) {
  		int i =0 , j = arr.length-1;
  		while(i>=j) {
  			int temp = arr[i];
  			arr[i] = arr[j];
  			arr[j] = temp;
  			i++;
  			j--;
  		}
  	}
  	static long[] rvrs(long[] arr) {
  		int i =0 , j = arr.length-1;
  		int n = arr.length;
  		long[] ans = new long[n];
  		for( i =0 ; i<n ; i++)
  			ans[i] = arr[j--];
  		return ans;
  	}
  
  	static long mod_mul(long a , long b ,long mod) {
  		return ((a%mod)*(b%mod))%mod;
  	}
  	 static long gcd(long a, long b)
  	  {      
  	     if (b == 0)
  	        return a;
  	     return gcd(b, a % b); 
  	  }
  	 static boolean[] prime(int num) {
  			boolean[] bool = new boolean[num];
  		     
  		      for (int i = 0; i< bool.length; i++) {
  		         bool[i] = true;
  		      }
  		      for (int i = 2; i< Math.sqrt(num); i++) {
  		         if(bool[i] == true) {
  		            for(int j = (i*i); j<num; j = j+i) {
  		               bool[j] = false;
  		            }
  		         }
  		      }
  		      if(num >= 0) {
  		    	  bool[0] = false;
  		    	  bool[1] = false;
  		      }
  		      
  		      return bool;
  		}
  
  	 static long modInverse(long a, long m)
  	    {
  	        long g = gcd(a, m);
  	       
  	          return   power(a, m - 2, m);
  	        
  	    }
  	   
  	 static long power(long x, long y, long m){
  	        if (y == 0) return 1; long p = power(x, y / 2, m) % m; p = (int)((p * (long)p) % m);
  	        if (y % 2 == 0) return p; else return (int)((x * (long)p) % m); }
  	   
       static class Combinations{
  	    	 private long[] z;
  	    	 private long[] z1;
  	    	 private long[] z2;
  	    	 long MOD;
  	    	  public Combinations(long N , long mod) {
  	    		  MOD  = mod;
  				z = new long[(int)N+1];
  				z1 = new long[(int)N+1];
  				z[0] = 1;
  				for(int i =1 ; i<=N ; i++) z[i] = (z[i-1]*i)%MOD;
  			     z2 = new long[(int)N+1];
  				z2[0] = z2[1] = 1;
  			    for (int i = 2; i <= N; i++)
  			        z2[i] = z2[(int)(MOD % i)] * (MOD - MOD / i) % MOD;
  			    
  			    
  			    z1[0] = z1[1] = 1;
  			    
  			    for (int i = 2; i <= N; i++)
  			        z1[i] = (z2[i] * z1[i - 1]) % MOD;
  			}
  	    	  long fac(long n) {
  	    		  return z[(int)n];
  	    	  }
  	    	  long invrsNum(long n) {
  	    		  return z2[(int)n];
  	    	  }
  	    	  long invrsFac(long n) {
  	    		  return invrsFac((int)n);
  	    	  }
  	    	  long ncr(long N, long R)
  	    	  {		if(R<0 || R>N ) return 0;
  	    		    long ans = ((z[(int)N] * z1[(int)R])
  	    		              % MOD * z1[(int)(N - R)])
  	    		             % MOD;
  	    		    return ans;
  	    		}
  	      }
  	      static class DisjointUnionSets {
  			    int[] rank, parent;
  			    int n;
  			  
  			    public DisjointUnionSets(int n)
  			    {
  			        rank = new int[n];
  			        parent = new int[n];
  			        this.n = n;
  			        makeSet();
  			    }
  			  
  			    void makeSet()
  			    {
  			        for (int i = 0; i < n; i++) {
  			          
  			            parent[i] = i;
  			        }
  			    }
  			  
  			    int find(int x)
  			    {
  			        if (parent[x] != x) {
  			        
  			            parent[x] = find(parent[x]);
  			  
  			        }
  			  
  			        return parent[x];
  			    }
  			  
  			    void union(int x, int y)
  			    {
  			        int xRoot = find(x), yRoot = find(y);
  			  
  			        if (xRoot == yRoot)
  			            return;
  			  
  			        if (rank[xRoot] < rank[yRoot])
  			  
  			            parent[xRoot] = yRoot;
  			  
  			        else if (rank[yRoot] < rank[xRoot])
  			  
  			            parent[yRoot] = xRoot;
  			  
  			        else
  			        {
  			            parent[yRoot] = xRoot;
  			  
  			            rank[xRoot] = rank[xRoot] + 1;
  			        }
  			    }
  			}
  	      static int[] KMP(String str) {
  	    	  int n = str.length();
  	    	  int[] kmp = new int[n];
  	    	  for(int i = 1 ; i<n ; i++) {
  	    		  int j = kmp[i-1];
  	    		  while(j>0 && str.charAt(i) != str.charAt(j)) {
  	    			  j = kmp[j-1];
  	    		  }
  	    		  if(str.charAt(i) == str.charAt(j)) j++;
  	    		  kmp[i] = j;
  	    	  }
  	    	  
  	    	  return kmp;
  	      }
  	      
  	      
  /************************************************ Query **************************************************************************************/	  
  	 
  /***************************************** 		Sparse Table	********************************************************/
  	      static class SparseTable{
  	    		
  	    		private long[][] st;
  	    		
  	    		SparseTable(long[] arr){
  	    			int n = arr.length;
  	    			st = new long[n][25];
  	    			log = new int[n+2];
  	    			build_log(n+1);
  	    			build(arr);
  	    		}
  	    		
  	    		private void build(long[] arr) {
  	    			int n = arr.length;
  	    			
  	    			for(int i = n-1 ; i>=0 ; i--) {
  	    				for(int j = 0 ; j<25 ; j++) {
  	    					int r = i + (1<<j)-1;
  	    					if(r>=n) break;
  	    					if(j == 0 ) st[i][j] = arr[i];
  	    					else st[i][j] = Math.min(st[i][j-1] , st[ i + ( 1 << (j-1) ) ][ j-1 ] );
  	    				}
  	    			}
  	    		}
  	    		public long gcd(long a  ,long b) {
  	    			if(a == 0) return b;
  	    			return gcd(b%a , a);
  	    		}
  	    		public long query(int l ,int r) {
  	    			
  	    			int w = r-l+1;
  	    			int power = log[w];
  	    			return Math.min(st[l][power],st[r - (1<<power) + 1][power]);
  	    		}
  	    		private int[] log;
  	    		void build_log(int n) {
  	    			log[1] = 0;
  	    			for(int i = 2 ; i<=n ; i++) {
  	    				log[i] = 1 + log[i/2];
  	    			}
  	    		}
  	    	}
  	      
  	      
  /********************************************************	Segement Tree	*****************************************************/
  /**
  	 	 static class SegmentTree{
  			 long[] tree;
  			 long[] arr;
  			 int n;
  			 SegmentTree(long[] arr){
  				 this.n = arr.length;
  				 tree = new long[4*n+1];
  				 this.arr = arr;
  				 buildTree(0, n-1, 1);
  			 }
  			 
  			 
  			  void buildTree(int s ,int e  ,int index ) {
  					if(s == e) {
  						tree[index] = arr[s];
  						return;
  					}
  				
  					int mid = (s+e)/2;
  					
  					buildTree( s,  mid, 2*index);
  					buildTree( mid+1, e, 2*index+1);
  					
  					tree[index] = Math.min(tree[2*index] , tree[2*index+1]);
  				}
  			  
  			 long query(int si ,int ei) {
  				 return query(0 ,n-1 , si ,ei , 1   );
  			 }
  			 private long query( int ss ,int se ,int qs , int qe,int index) {
  					
  					if(ss>=qs && se<=qe) return tree[index];
  					
  					if(qe<ss || se<qs) return (long)(1e17);
  					
  					int mid = (ss + se)/2;
  					long left = query( ss , mid , qs ,qe , 2*index);
  					long right= query(mid + 1 , se , qs ,qe , 2*index+1);
  					return Math.min(left, right);
  				}
  			 public void update(int index , int val) {
  				 arr[index] = val;
  				 for(long e:arr) System.out.print(e+" ");
  				 update(index , 0 , n-1 , 1);
  			 }
  			 private void update(int id ,int si , int ei , int index) {
  				 if(id < si || id>ei) return;
  				 if(si == ei ) { 
  					 tree[index] = arr[id];
  					 return;
  				 }
  				 if(si > ei) return;
  				 int mid = (ei + si)/2;
  					
  					update( id,  si, mid , 2*index);
  					update( id , mid+1, ei , 2*index+1);
  					
  					tree[index] = Math.min(tree[2*index] ,tree[2*index+1]);
  			 }
  			  
  		 }
  		 */
  
  /* ***************************************************************************************************************************************************/	 
  	 
  	      static Reader sc = new Reader();
  	 static StringBuilder sb = new StringBuilder();
  	 public static void main(String args[])  {
  	
  		 int tc = 1;
  		  tc = sc.nextInt();
  		 
  		  for(int i = 1 ; i<=tc ; i++) {
  
  //			 sb.append("Case #" + i + ": "  );	// During KickStart && HackerCup
  			 TEST_CASE();
  			 
  		 }
  		 System.out.println(sb);
  
  	 }
  
  	static void TEST_CASE() {
  		int n = sc.nextInt();
  		char gc = sc.next().charAt(0);
  		String str = sc.next();
  		if(bool(str, gc)) return;
  		if(str.charAt(n-1) == gc) {
  			sb.append("1\n");
  			sb.append(n+"\n");
  			return;
  		}
  		ArrayList<Integer> al = new ArrayList<>();
  		for(int i =0 ; i<n ; i++) {
  			if(str.charAt(i) != gc) al.add(i+1);
  		}
  		int gcd = 0;
  		for(int e:al) gcd = (int)gcd(gcd , e);
  		boolean[] visit = new boolean[n+1];
  		for(int i = 2 ; i<=n ; i++) {
  			boolean cond = true;
  			for(int j = i ; j<=n ; j+=i) {
  				if(str.charAt(j-1) != gc) {
  					cond = false;
  					break;
  				}
  			}
  			visit[i] = cond;
  		}
  		for(int i =2 ; i<=n ; i++) {
  			if(visit[i]) {
  				sb.append("1\n");
  				sb.append(i+"\n");
  				return;
  			}
  		}
  		sb.append("2\n");
  		sb.append((n-1)+" "+(n)+"\n");
  		
  	}
  	static boolean bool(String str , char c) {
  		for(char cc:str.toCharArray()) {
  			if(cc != c) return false;
  		}
  		sb.append("0\n");
  		return true;
  	}
  }
  
  /*******************************************************************************************************************************************************/
  
  /**
  
   */
  
  
  
  
  
  
  