What Will Be The Output Of The Following Java Codep Pre #817

 class A { int a = 10; } class B extends A { int b = 20; } class C extends B { int c = 30; } class D extends C { public void calculate() { System.out.println(a*b*c); } } public class Multilevel { public static void main(String[] args) { D d = new D(); d.calculate(); } }