Consider the relations Students, Faculty, Courses, Rooms, Enrolled, Question 18 [6 marks] Teaches, and MeetsIn: Students(sid: string, name: string, login: string, age: integer, gpa: real) Faculty(fid: string, fname: string, sal: real) Courses(cid: string, cname: string, credits: integer) Rooms(rno: integer, address: string, capacity: integer) Enrolled(sid: string, cid: string, grade: string) Teaches(fid: string, cid: string) MeetsIn(cid: string, rno: integer, time: string) (a) [3 marks List all the foreign key constraints among these relations (where the foreign keys are and what relation they actually belong to). (b) [1 mark] Circle all the relations that are entity-sets above. (c) [1 mark] Put an asterisks (i.e. *) beside the relations that are relationships above. (d) [1 marks] Give an example of a (plausible) constraint involving one or more of these relations. This constraint cannot be: a primary key constraint, a foreign key constraint, nor any type of domain-level constraint