4 Consider the following schemas for a course registration system Student Number. firstName, last Name, streeetAddress, city, state, zipcode) Course(sourseld. course Number, section Number, year, semester, course Title, hours instructor) RegisteringForCourse( iNumber, souseld) a).In the relation(table) Course, do you find another key among the attributes? If you do, list the attributes of the key you found. (7 pts) b).Do you see any table that implements a relationship? If you do, deseribe how that table(representing a relationship) relates other tables(entitis)? (8 pts) c). Write a SQL, statement that will return all the courses that all the students take. The result set tes: jNumber, first Name, last Name, course Number, section Number, year and semester. Also write a relational algebra expression to do the same. (10 pts) d).Write a SQL statement that will return jNumber, firstName, lastName of all students who take Ann Smith's courses. Note that the attribute instructorAnn Smith' Also write a relational algebra expression to do the same (10 pts)