QUESTION 3 (18 marks) (a) The software for a system for student self-registration has been developed. Use cases have been identified for this system and the main scenario of the "SelfRegister" use case is as follows: Preconditions: Student already logged in and authenticated. 1. The student chooses to register for course and year. 2. The system responds with the available mandatory and optional modules for the course and year. (The optional modules available will depend on course specific rules. The number of optional modules that may be taken depends on the number of mandatory modules for the course.) 3. The student submits their desired choice of optional modules for the course and year. 4. The system checks that the combination of optional modules chosen is permitted and confirms that it is (Potential restrictions which need to be checked include the following: the student's academic record must be checked to see that prerequisite modules were passed; for certain modules, eligibility depends on a student's previous year grade being sufficiently high; and university wide timetabling may make certain module combinations impossible.) (Assume that the remainder of the scenario is not relevant to the question.) (1) Sketch a system sequence diagram for this scenario. (ii) Design the realization of this scenario by assigning responsibilities to classes and document with a communication diagram. (Do not use a sequence diagram.)