A retail store has a preferred customer plan where customers can earn discounts on all their purchases. The amount of a customer's discount is determined by the amount of the customer's cumulative purchases in the store, as follows: When a preferred customer spends $500, they get a 5% discount on all future purchases. When a preferred customer spends $1,000, they get a 6% discount on all future purchases. When a preferred customer spends $1,5000, they get a 7% discount on all future purchases. When a preferred customer spends $2,000, they get a 10% discount on all future purchases. Design a class named PreferredCustomer, which inherits from the Customer class you created in Exercise 7. The preferredCustomer class should have int fields for the amount of the customer's purchases and the customer's discount level. Write a constructor that initializes these fields as well as accessor and mutator methods. Desmonstrate the class in a program that prompts the user to input the customer's name, address, phone number, customer number, whether they want to recieve mail, and the amount they've spent, and then uses that information to create a PreferredCustomer object and print its information. (Use string formatting to print the amount spent.) Create all of the classes in the same file by not delcaring any of them public. SAMPLE RUN