If Q is a positive integer, which of the following must be odd? Pick.
A) Q+1  B) Q^2+Q  C) Q^2+Q+1  D) x^2−1  E) 3x^2−3
A. Q+1 = can be odd or even. Since O + O =E or E + O = O   B. Q^2 + Q = Q(Q+1). Since from the above derivation we already know the term Q+1 can be Odd or Even, directly substitute here. Q(ODD) = Even (When Q is Even) or Q(EVEN) = EVEN [When Q is ODD]   C. Here's the answer. Since we know the term Q^2 + Q can always take a EVEN number, EVEN + 1 = ODD   Hence Q^2+Q+1.
<result>C</result>
If Q is a positive integer, which of the following must be odd?