Consider the inheritance of classes from Exercise R-2.12, and let d be an object variable of type Horse. If d refers to an actual object of type Equestrian, can it be cast to the class Racer? Why or why not?

In Exercise R-2.12

Draw a class inheritance diagram for the following set of classes:

• Class Goat extends Object and adds an instance variable tail and methods milk( ) and jump( ).

• Class Pig extends Object and adds an instance variable nose and methods eat(food) and wallow( ).

• Class Horse extends Object and adds instance variables height and color, and methods run( ) and jump( ).

• Class Racer extends Horse and adds a method race( ).

• Class Equestrian extends Horse and adds instance variable weight and is-Trained, and methods trot( ) and isTrained( ).