Which XXX would replace the missing statement in the following algorithm to insert a new node after curNode in a doubly linked list? X insertAfter (list, curvode, newNode) { if (list.head == null) { list.head = newNode list.tail = newNode } XXX { list.tail.next = newNode newNode.prev = list.tail list.tail = newNode } else { sucNode = curNode.next newNode.next = sucNode newNode.prev = curNode curNode.next = newNode sucNode.prev = newNode } Answers: a. else if (curNode == list.tail) b. else if (curNode != list.head) c. else if (sucNode == list.tail) d. else if (curNode == list.head)