Answer is : - C
Algorithm goes like this :--
Step 1 - Find out length of both linked lists , which takes :- Q(m+n).
Step 2 - Reverse both linked lists which again takes :- Q(m+n).
Step 3 - Traverse in lock mode as long as you get same items which O(min(m,n)).
Step 4 - At the end of step 3 you get the intersecting node.
Step 5 - Reverse linked lists back , which takes Q(m+n).
Hence time complexity comes out to be Q(m+n).