40. show() Base x=A() #you can also try this class Base; x.show() array = [ A(),B(),C() ] class A extends Base; x=B() for x in array: class B extends Base; x.show() x.show() class C extends Base; x=C() Base x; x.show() x= new B(); x.show(); or interface Base, whatever. show() A show() B show() C