Yeah if we're talking about only existing link. Only 2.
Answer is correct --> 1
Here question ask modification in existence link only which will be the last link -> right pointer updated to point new last link, though we also modify new last link -> left to point to original last link [which is now second last].
what it was previously?
last_link -> right =NULL;
new_last_link -> left= last_link -> right;
new_last_link ->right =NULL;
I think modification of only 2 pointers is need .
1. Make it the last link
2. Make pointer to the previous node.
This might help..