You have been requested to develop a Gas Station System with the following characteristics: To simplify this case study, the payment services in a gas station system are confined to pay by credit, and pay by debit card. In the credit card payment, a driver inserts his credit card to card reader that reads the driver’s card information. The credit card data is sent to a financial institution that issued the card where the credit card is validated. If the credit card is valid, the driver is allowed to pump gas. The debit card payment is similar to the credit card payment, except for the driver should provide a PIN number that is used to validate the debit card. If enabled, the driver selects the grade of gas he desires and pumps gas until he turns off the pump by throwing a switch. The amount of gas that a gas station has is updated when the gas is sold. Then the cost of the sale is computed at the pump and the amount is transmitted back to the financial institution where it is entered as a charge in the driver’s corresponding credit card account. A receipt is issued at the pump. The data about the sale are stored in the gas station. The pump returns to the idle state. A daily summary report for the gas station sales is generated automatically every night at 1:00 AM and sent to a gas station printer. The report may include the amount of each type of gas sold (i.e., Regular, Premium, and Super Premium), the total sales for each type of gas, and grand total of sales of a day. A gas station manager can also look at each daily summary report using his/her personal computer. The gas in the system will be refilled by the gas truck driver on a daily basis. Each type of gas (i.e., Regular, Premium, and Super Premium) is stored in gas tanks physically, and the amounts of each type will be updated in the system. The amount of each type of gas will be reduced when a driver has purchased it.