a) [5 pts) Let R be a relation with schema (A1, A2, ..., A, B1, B2, ..., Bm) and let S be a relation with schema (B1, B2, ..., Bm); that is, the attributes of S are a subset of the attributes of R. The quotient of Rand S, denoted by, R-S (or R/ S), is the set of tuples t over attributes A1, A2, ..., An (i.e., the attributes of R that are not attributes of S) such that for every tuple sin S, the tuple ts, consisting of the components of t for A1, A2, ..., An and the components of s for Bi, B2, ..., Bm, is a member of R. Give an expression in Relational Algebra, using the basic operators of Relational Algebra, that is equivalent to R-S. b) [15 pts) Show the result of the division operations A/B1, A/B2, and A/B3 for the following relations: B1 B2 B3 sno pno pno pl pno pl P2 p3 s103 p3 D4 p4 s1p4 s2pl s2p2 s2 p4 A p3