(10 p + q)/3

[sanju09]

If p and q are integers, is (10 p + q)/3 an integer?

(1) q = 5

(2) p q is even

[DanaJ]

(10p + q)/3 is an integer means that 10p + q is divisible by three, which means that the sum of its digits is a number divisible by three.
1. is insufficient since you don't know anything about p
2. is insufficient since p*q = even does not help us in clearing this situation.
Take the two stmts together and you don't get anything else except for the fact that p is even. P can be anything: 2, 4....

So E is my answer.