(a) Consider the following use case for a web site customer signing up for an account. A user signs up for a new account using a web browser. She enters personal details onto a web form, which are uploaded to a web application server and validated and then saved in a database. A mail server then sends the user a confirmation email with an 'accept' link. The user reads the email using her mail client. She clicks accept on a hyperlink embedded in the email, and is then marked in the database as a confirmed user, and a confirmation acknowledgment is sent to the browser. Draw a UML sequence diagram to model the interactions between the agents involved in this transaction (the entities italicised in the use-case), indicating the type of each HTTP request. (b) A management system for a university includes the following Java classes. (Methods are not shown). class Student { String regno, name; List modules; } class Module { String code, name; List students; } (i) Write a JSP fragment that will display in tabular form the names and codes of all of the modules taken by a student, and also the total number of such modules. You should assume that a reference to the student is available in a variable called stud of type Student. (ii) Briefly describe one weakness in the design of the classes shown above and suggest a better approach.