Given the following class:public class Cat{    long length;    public Cat(long l)    {        length = 1;    }    public static void main(String arg[])    {        Cat c1, c2, c3;        c1 = new Cat(10L);        c2 = new Cat(10L);        c3 = c2;        long m = 21L;    }}Which expression returns true?

• A.c1==c2;

• B.c2==c3;

• C.m==c1;

• D.c1.equals(m).