x and y are positive integers. If y + x is odd, then which of the following must be even? Choose one:
A) x	B) y	C) x + y	D) xy − x	E) x^2 − y
Given that y + x is odd,   Hence x is odd, Answer will be x + y.
<result>C</result>
x and y are positive integers. If y + x is odd, then which of the following must be even?