Given the Partial ArrayList Class Declaration Below, Select an Expression

Given the partial ArrayList 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 ArrayList
{
Private Object[] elements;
Private int currentSize;
Public ArrayList()
{
Final int INITIAL_SIZE = 10;
Elements = new Object[INITIAL_SIZE];
CurrentSize = 0;
}
Public boolean empty()
{
Return ________________________ ;
}
}

A) elements.length == 0
B) elements.currentSize == 0
C) elements[0] == null
D) currentSize == 0