QUESTION 2 (15 marks) (a) A system for making flight reservations is to be developed. A customer who wishes to make a flight reservation will want to know which flights are available for a given destination (with the corresponding times and fares). The customer may also wish to know which destinations are available. They can then reserve specific seats (by seat row and position) on the aircraft. Customers pay for flight reservations by credit card. A remote credit card clearing company (e.g. Visa) will authorize credit card payments. Once authorised, customers are given a reservation number. When the customer arrives at the airport they present their reservation number to get a boarding pass for the flight Document the domain model (about 6 classes) for this system