$(17 - 1）\times 3 = 48$ 
Workers want to plant some trees between houses. There are $17$ houses on one side of a road. Workers want to plant three trees between every two adjacent houses. How many trees do they need to plant? 
a: $$45$$ 
b: $$48$$ 
c: $$51$$ 
d: $$54$$ 
e: $$57$$ 