Add a class MultiChoiceQuestion to the question hierarchy of Section 9.1 that allows multiple correct choices. The respondent should provide all correct choices, sepa- rated by spaces. Provide instructions in the question text.

Add a method addText to the Question superclass and provide a different implementa- tion of ChoiceQuestion that calls addText rather than storing an array list of choices.

Provide toString methods for the Question and ChoiceQuestion classes.

Implement a superclass Person. Make two classes, Student and Instructor, that inherit from Person. A person has a name and a year of birth. A student has a major, and an instructor has a salary. Write the class declarations, the constructors, and the methods toString for all classes. Supply a test program that tests these classes and methods.

Make a class Employee with a name and salary. Make a class Manager inherit from Employee. Add an instance variable, named department, of type String. Supply a method toString that prints the manager's name, department, and salary. Make a class Execu­ tive inherit from Manager. Supply appropriate toString methods for all classes. Supply a test program that tests these classes and methods.