The last fraction should be $\frac{85}{89}$, so the answer is $\frac5{89}.$ 
Joe writes an expression $\frac59\times\frac9{13}\times\frac{13}{17}\cdots $ Following the pattern, he writes middle fraction is \frac{45}{49}. What is the result of the expression? 
1: $\frac5{49}$ 
2: $\frac5{89}$ 
3: $\frac5{17}$ 
4: $\frac1{31}$ 
5: $\frac5{81}$ 