Given two sorted list of size '$m$' and '$n$' respectively. The number of comparisons needed in the worst case by the merge sort algorithm will be :

OPTION D

The number of comparisons needed in the worst case by the merge sort algorithm will be m+n-1 i.e. only last element will not be compare only.

https://gateoverflow.in/60115/ugcnet-dec2013-ii-25

The number of comparisons needed in the worst case by the merge sort algorithm will be m+n-1 .