If $a$ and $b$ are integers and $a-b$ is even. which of the following must always be even?
(A) $a b$
(B) $a^{2}+b^{2}+1$
(C) $a^{2}+b+1$
(D) $a b-b$

Question ID - 156781 | SaraNextGen Top Answer

If $a$ and $b$ are integers and $a-b$ is even. which of the following must always be even?
(A) $a b$
(B) $a^{2}+b^{2}+1$
(C) $a^{2}+b+1$
(D) $a b-b$