.Given two sorted lists of size m and n respectively.The number of comparisons needed in the worst case by the merge sort algorithm will be?A mnB max(m,n)C min(m,n)D m+n-1

The answer is D. m+n-1.

Here's why:

The merge process of the merge sort algorithm works by taking the smallest unprocessed element from the input lists and putting it in the output list. This is done by comparing the smallest unprocessed elements of the input lists.

In the worst case, every element from both lists will be compared with an element from the other list exactly once, before it is put in the output list.

So, if the sizes of the two lists are m and n, the total number of comparisons in the worst case will be m+n-1.

This is because the last insertion does not require a comparison, as there is no other element to compare it with. Hence, the '-1' in the formula.