A use case diagram is drawn for an 11-module banking system. The Retail Institution and User actors interact with the M_Transaction module, which includes M_InsertCard and its extension M_InvalidCard. M_InsertCard is included in M_ATMTransaction, which also includes M_PinValidation and its extension M_InvalidPin. M_OnlineTransaction and M_ClientDesktopTransaction both include M_LogIn and M_LogOut, with M_InvalidLogIn extending M_LogIn. The BankDatabase actor interacts with M_Transaction, M_ATMTransaction, M_OnlineTransaction and M_ClientDesktopTransaction. The User actor interacts with M_ATMTransaction and M_Online