please try all parts

(22 marks) (b) Consider the software used by a car rental company. It consists of two parts: the central system, which customers access via a website, and the agent system used at the car rental location. A customer wishing to rent a car will usually reserve the rental in advance using the website. There they supply their name, address, and other details, the type of car they want, and the dates and times they want it for. The central system then locks in a rental rate and creates a reservation. Users can view, modify, and cancel their reservations at any time (although there may be a cost associated with cancellation). When the customer arrives at the rental location, they deal with the car rental agent who uses the agent system. The agent looks up the customer using the system and prints out the contract details which the customer must sign. The customer must also provide their driving licence. If this is all OK, the agent checks the available cars which best match the reservation criteria using the system. After selecting one (in agreement with the customer), the agents marks the car out on the system and hands over the keys. If the customer does not have a reservation or there is a problem with the reservation it is often possible for the agent to create a new rental from scratch by entering all the necessary information, assuming there are suitable cars available. After the customer finishes with the car they must return it and at this point another rental agent checks over the car to make sure everything is OK and then marks the car returned using the agent system. (i) Write down an actor-goal list for the agent system including a brief (one line) description of each actor. (ii) For the "rent car" use case, write the detailed form of the main scenario. In addition, write the brief form of all extension/alternate scenarios you can identify. (The brief form should indicate the condition in which the extension occurs and the basic course of action it results in.) (iii) Sketch a use case diagram to summarize the system