4. Given a student registration system for the University of ABC. The university has Fall, Spring and Summer semesters for undergraduate and graduate classes. The student can register or drop any course before the deadline. Late registration and drop will be penalized by a certain amount of payment. Each undergraduate student can register at most 5 courses and minimum 3 courses. Each graduate student can register at most 3 courses and minimum 2 courses. All of the courses can be registered online. Each course has certain capacity (you can assume any number, e.g., 30). Your task is to model this simple registration system using correct UML notation. You need to define data, two operations (register and drop) and corresponding schemas