10. (15 points) Prove that the Merge-Sort pseudocode shown in Question 5 is correct. That is, prove that Merge-Sort(A, p, r) sorts the subarray A[p...r] in increasing order. You can assume that Merge(A, p, q, r) successfully merges two sorted arrays, Ap...q) and Aq + 1...r], into a sorted array A[p...r]. Please do not forget the base case