(1 point) For each sequence a, find a number k such that nkan has a finite non-zero limit. (This is of use, because by the limit comparison test the series an and n both converge or both n=1 n=1 diverge.) A. an (4+ 2n)-2 k = 2 . k = 2n2+2n+2 C. an 6n +6n+2 k = 9. 2n2+2n+4 6n+6n+2 n D. n k =