If n is an odd integer, which of the following must also be an odd integer?
Choose the correct choice from the following answers:
A) 2n B) 2n^2 C) n^2 + 2n D) n^2 + 3n E) n^2 + 2n + 3
(A)	2n = even*odd = even.   (B)	2n^2 = even*odd = even.   (C)	n^2 + 2n = odd + even*odd = odd + even = odd.   (D)	n^2 + 3n = odd + odd*odd = odd + odd = even.   (E)	n^2 + 2n + 3 = odd +even + odd = even.   Answer: n^2 + 2n.
<result>C</result>
If n is an odd integer, which of the following must also be an odd integer?