1. Suppose relation R(A,B,C) has the tuples ABC difference, compute TAB(R)-PS(AB) Using bag projection (aB cR)). Note that the renaming is only to give the two projections the same schema. Which of the following is true about the tuples that appear in the result? a) (2,2) does not appear in the result. b) (2,3) does not appear in the result. c) (1,2) appears twice in the result. d) (2,3) appears -1 times in the result. 2. Let R(A,B,C) and S(A,B,C) be two relations. Which of the following is true if R, S, and all operations are interpreted to be sets and set operations, but not necessarily true if R, S and all operations are bags and bag-operations? a) (((R-S) [union] (S-R)) b) (RnR)-R c) (R [union] S) S (R S)-[emptyset]