Assume the following method is within the SingleLinkedList class, what does it do? public void Undefined(E item1, E item2) { Node ptr = head; while (ptr != null) { if(ptr.data.equals(item1)) { head = new Node(item2, head); return; } ptr=ptr.next; } } A) Adds a node before the first node with its data as item2, if item1 exists as data of the first node in the list. B Adds a node after the last node with its data as item2, if item1 exists anywhere in the list. Adds a node before the first node with its data as item2, if item1 exists anywhere in the list. D Adds a node after the last node with its data as item2, if item1 exists as data of the first node in the list