What is the output of this program?

(a) Error
(b) Hello
(c) 36
(d) Hello 36

import java.util.*; public class genericstack { Stack stk= new Stack (); public void push (E obj) { stk.push(obj); } public E pop () { } } } class Output ( public static void main (String args []) { genericstack gs = new genericstack (); E obj = stk. pop (); return obj; } gs.push ("Hello"); System.out.print (gs.pop() + " "); genericstack gs = new genericstack (); gs.push (36); System.out.println (gs.pop());