This exercise concerns a simplified system of a supermarket cash register. It is inspired to a great extent by the case study of C. Larman's first book (the Point-of Sale System), which formed the basis of the Valtech training about OOAD. The standard procedure of using a cash register is as follows: a. A customer arrives at the checkout to pay for various items actor b. The cashier records the bar code number of each item, as well as the quantity if it is greater than one. C actor The cash register displays the price of each item and its description. When all the purchases are recorded, the cashier indicates the end of the sale. The cash register displays the total cost of the purchases. The customer selects his or her payment method: . Cash: the cashier takes the money from the customer and puts it in the cash register, the cash register indicates how much change the customer is to be given; Cheque: the cashier verifies that the customer is financially solvent by sending a request to an authorization center via the cash register; . Credit card: a banking terminal forms part of the cash register. It sends a request for authorization to an authorization center, according to the card type. g. The cash register records the sale and prints a receipt. h. The cashier gives the receipt to the customer. Once the items have been entered, the customer can present money-off vouchers for certain items to the cashier. When the payment transaction is finished, the cash register sends the information on the number of items sold to the stock management system. Every morning, the shop manager initializes the cash registers for the day. 1. Define a use case diagram of the cash register system.