If x and y are unique prime integers, which of the following must be even?
Options:
(A) x−y
(B) x−2y
(C) 2x−2y
(D) 2x−y
(E) xy^2 Now, let's think a bit. Some random thoughts:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Any number multiplied by 2 has to be an even number
The final answer: (C).