If x and y are prime numbers then which one of the following

If x and y are prime numbers, then which one of the following cannot equal x – y ? (Please answer with explination!!!)

(A) 1

(B) 2

(D) 14

(E) 20

As we know that prime numbers are 2,3,5,7,11,13,17,19,..............

If X and Y are any prime numbers among them

Let X=3, Y=2 then X-Y = 1 is possible

Let X=5, Y=3 then X-Y=2 is possible

Let X=17, Y=3 then X-Y=14 is possible but 13 is not posible

so that 13 can not

Let X=23, Y=3 then X-Y=20 is possible