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 after the last node with its data as item2, if item1 exists anywhere in the list.
	b.	Adds a node after the last node with its data as item2, if item1 exists as data of the first node in the list.
	c.	Adds a node before the first node with its data as item2, if item1 exists as data of the first node in the list.
	d.	Adds a node before the first node with its data as item2, if item1 exists anywhere in the list.