If c and d are unique prime integers, which of the following must be even?\nOptions:\n(A) c−d\n(B) 2c−2d\n(C) c−2d\n(D) 2c−d\n(E) cd^2
Let's be accurate as possible and think first.
(B)
Any number multiplied by 2 has to be an even number.

Final answer: (B)