ANSWER: (1) Deleting a node whose location is given.
In this question, we can simply eliminate the (2) and (4) from our choice, since in both the cases we need to visit every node one after other. Doubly LL will serve no extra good in these two cases as we need to proceed from starting node and go until the last note in LL or vice-versa .
(2) To insert a new node in the LL after some specific node, we need not go back to the previous node in the LL. And thus, doubly LL will serve no purpose in this case too.
At last, in the case of (1) we are supposed to delete the node (say x) whose location is given. Which means that before we remove node x from the LL we need to store the address of next node in the list, linked to node x in the address field of node just before node x (which currently store the address of node x). Since we need to go back-and-forth in the list during this operation, doubly linked list will be a good help in increasing the efficiency by decreasing the time required for the operation.
LL referes to Linked List