If t is an odd integer, which of the following must also be odd?  Select the correct option:
A) 2t + 8 B) t + t C) 3t + 3 D) 2t + t E) t^2 + 1
Things to keep in mind:   Odd + odd = even   Odd + even = odd   Odd*odd = odd   Odd*even = even   On checking each option   A. 2t + 8   2t = even, 2t + 8 = even + even = even.   B. t + t   Odd + odd = even. This will be even   C. 3t + 3   3t = odd, 3t + 3 = odd + odd = even   D. 2t + t   2t = even, 2t + t = even + odd = odd   E. t^2 + 1   t^2 = odd, t^2 + 1 = odd + odd = even   Correct option: 2t + t
<result>D</result>
If t is an odd integer, which of the following must also be odd?