part c only. please have a clearer diagram. Thanks!

- Every department has a unique dname. - Every professor has a unique pid. - Every student has a unique sid. - Every course has a unique cid. - Every course can be uniquely identified by its cid and cname. - A professor works in exactly one department. - A department contains at least one professor. - A professor can teach any number of courses to a student (it could be zero). a) List all the superkey(s) of "Course". (5 marks) b) List all the candidate key(s) of "Course". (4 marks) c) Assume that cid is a primary key, complete the ER-diagram by adding all missing constraints (weak entity, key constraints, participation constraints and relationship constraints). ( 6 marks)