3. A school has hired you to create a database management system to assist in scheduling classes. After several interviews with the president, you have come up with the following list of entities, attributes, and initial business rules:

• Room is identified by BuildingID and RoomNo and also has a Capacity. A room can be either a lab or a classroom.
• Instructor is identified by EmpID and has attributes Name, Rank, and OfficePhone.
• Timeslot has identifier TSIS and has attributes DayOfWeeks, StartTime, and EndTime.
• Course has identifier CourseID and has attributes CourseDescription and Credits. Courses can have one, none, or many prerequisites. Courses also have one or more sections.
• Section has identifier SectionID and attribute EnrollmentLimit

After some further discussions, you have come up with some additional business rules to help you create the initial design:

• An instructor teaches one, none, or many sections of a course in a given semester.
• An instructor specifies preferred timeslots.
• Scheduling data are kept for each semester, uniquely identified by semester and year.
• A room can be scheduled for one section or no section during one timeslot in a given semester of a given year. One room can participate in many schedules, one schedule, or no schedules; one timeslot can participate in many schedules, one schedule, or no schedules.

Develop an ER model based on these business rules.