Given the Partial LinkedList Class Declaration Below, Select an Expression

Given the partial LinkedList class declaration below, select an expression to complete the empty method, which is designed to return true if the list contains no elements. public class LinkedList
{
Class Node
{
Public Object data;
Public Node next;
}
Private Node first;
) . .
Public boolean empty()
{
Return ________________________ ;
}
}

A) first != null
B) first == null
C) first.data == null
D) first.next == null