If \(x\) and \(y\) are positive odd integers, then which of the following must also be an odd integer?
I. \(x^{y+1}\)
II. \(x(y+1)\)
III. \((y+1)^{x-1}+1\)
A. I only
B. II only
C. III only
D. I and III
E. None of the above
Answer: A
Source: Magoosh