Consider a modification to merge sort algorithm on an array A of size n, where the two sub-arrays to be merge are copied into a temporary array C and then insertion sort is applied on C and then copied back into A, this procedure is repeated recursively, then the worst-case time complexity of the modified merge sort is
(A) theta (n logn)
(B) theta (n (logn)^2)
(C) theta (n^2)
(D) theta (n^2 logn)