If a is an odd integer, which of the following must be an even integer? Choose the most appropriate option:
A) a^4−a+1 B) (a^4−a)(a+1/a) C) a^4−a^3+a^2+2a D) (a^3+a^2+a)^2 E) None of the above
Let assume a be 1..   A. 1-1+1..odd   B.(1-1)(2) = 0.. even   C.1-1+1+2..odd   D.1+1+1..odd   E.None   Ans: option (a^4−a)(a+1/a).
<result>B</result>
If a is an odd integer, which of the following must be an even integer?