Rule 1:An object of a class can be referenced by a variable of the class type OR any of the class ancestor class types OR of the type of an Interface it implements.

Rule 2:Java only permits the methods of a reference variables class to be invoked on that variable

Rule 3:When an object and its reference variable have different class types, and a method that is in both classes in invoked on the object, the method of the objects class is selected for execution.

4. Of the three Rules presented in the pre-reading material which of the following create a situation where downcasting is necessary? Select one: a. Rule 1 b. Rule 2 c. Rule 3 d. Rule 1 and 2 e. Rule 2 and 3 f. Rule 1 and 3 g. Rule 1, 2 and 3