If p is an odd integer, which of the following must also be odd?
Options.
A) 4p + 4  B) p + p  C) 3p + 3  D) 2p + p  E) p^2 + 1
Things to keep in mind:   Odd + odd = even   Odd + even = odd   Odd*odd = odd   Odd*even = even   On checking each option   A. 4p + 4   4p = even, 4p + 4 = even + even = even.   B. p + p   Odd + odd = even. This will be even   C. 3x + 3   3x = odd, 3x + 3 = odd + odd = even   D. 2p + p   2p = even, 2p + p = even + odd = odd   E. p^2 + 1   p^2 = odd, p^2 + 1 = odd + odd = even   Correct option: 2p + p
<result>D</result>
If p is an odd integer, which of the following must also be odd?