A vending machine is designed such that it accepts and returns only quarters and vends either cookie for a dollar, or vends chips for 75 cents, or vends water for 50 cents, or returns the money back when coin return is pressed.

It returns the balance money if any automatically after vending the product. The products are vended by activating the respective actuators. Assume the vending machine never runs out of vending products.

a. Draw a UML class diagram for the vending machine.

b. Draw a UML state diagram for the vending machine.

c. Draw the UML sequence diagram for vending peanuts and snacks.