Instructions: All Ouestions are based on the following case study. 1 You are required to design a system that will be used to take online exams. There are three 2 main groups of actors: teachers, students, and evaluators. Teachers and students are 3 human actors. Evaluators are more interesting as they can be human users, third-party 4 service providers, or paid third-party Al-based applications, 5 6. When teachers schedule exams, they can select/set marking criteria on a per-question 7 basis. Questions can be of different types. Currently, there are MCQ questions, multi-part 8 questions, reasoning questions, descriptive questions. In the future new types of questions 9 should be easy to add. For each question, the teacher can assign one or more evaluators. If 10 more than one evaluator is chosen, the teacher must also select a mark-decision strategy 11 Current strategies include average-mark, highest-mark, median-mark 12 gaussian-weighted-summation, etc. New mark decision strategies should be easy to add 13 in the future. 14 15 As this is an educational tool, it is required that the system integrates with the identity and 16 email services of different educational institutes. This can be done on an ongoing basis, 17 but your design should easily support such integration 1 Q1. Identify the Design Pattern(s) you will use to design the solution to the problem(s) mentioned in lines 6-13 Q2. Using the pattern(s) you mentioned in your answer to Q1. design a solution to the problem(s) mentioned in lines 6-13 of the case study. Express your solution as a UML Class diagram You only need to show attributes and methods when necessary to express your solution clearly Q3. Consider the method is Valid Mark( given Mark, mar Mark) which is required to return true if given Mark is valid. It will be valid if it is greater than or equal to zero and less than or equal to maxMark bool isValidMark( given Mark, maxMark) if (given Mark