Consider the following relational schema: Department (deptid, dname, location) Student (snum, sname, deptid, age) Faculty(fid, fname, deptid) Class(cname, deptid, meets at, room, faculty) Enrolled(snum, cname, score, grade) Assume that: All students and faculty members must major/work in one department; - Faculty teach courses only in the department they belong to: - The names of the courses are unique for each department - Scores are numbers in [0,100]; - Faculty in Table Class is a subset of fid in Table Faculty. Write each of the following queries using Query-by Example (QBE). If you believe any one of the following is not expressible in QBE, informally explain why it cannot be expressed. 4. (10 pts) Print the names of the students who are enrolled in the most number of courses. 5. (10 pts) Print the student ids with the maximum average score in the courses they have enrolled in. 6. (5 pts) Delete the departments that do not have any faculty or courses at all