Add a new class called ClassC, which is a subclass of ClassB, to Program 8.1. Make an initVar method that sets the value of its instance variable x to 300.Write a test routine that declares ClassA,...

Add a new class called ClassC, which is a subclass of ClassB, to Program 8.1. Make an initVar method that sets the value of its instance variable x to 300.Write a test routine that declares ClassA, ClassB, and ClassC objects and invokes their corresponding initVar methods.