A Queue Based on a Linked List Uses the Following

Multiple Choice

A queue based on a linked list uses the following code
Class Node{
String element;
Node next;
Node (String el,Node n) {
Element = el;
Next = n;
}
}
Node front = null,rear = null;
What is the right code for the boolean empty() method?

A) return front == null;
B) if (rear == front.return true;
Else
Return false;
C) if (front == null.
Throw new RuntimeException("Empty".;
Else
Return false;
Return true;
D) return front == rear;