Draw a class diagram based on the following requirements: 1. All instructors consist of professor, associate professor, and assistant professor. 2. Departments offer many courses, but a course is offered by one or more department. 3. Courses are taught by instructors, who may teach up to three courses. 4. Instructors are assigned to one department. 5. One instructor may chair a department. Extend the class diagram to include the following attributes: 1. A department includes the department ID (private), department name (public), and description about the department (public) 2. An instructor includes the instructor ID (private), instructor name (public) and department 3. A course includes the course ID (private), course name (public), course description (public), and prerequisite course (protected) Extend the class diagram to include the following operations: 1. Instructors can 2. Select course 3. Prepare course plan