Polymorphism - Polymorphism is the ability of an object to take on many forms. The most common use of polymorphism in OOP occurs when a parent class reference is used to refer to a child class object. Which one is polymorphism, and which one is not? class Window public void open) class ScrollableWindow extends Window @Override public void open( class DialogWindow extends Window @Override public void open( Question: which open functions were called? Window sw new ScrollableWindow() sw.open Window dw new DialogWindow dw.open)