Q:Question:C, and D, where functional dependencies B -> ACD and C -> D are supposed to hold. (18 points) Given a relational schema R with attributes A, B, C, and D, where functional dependencies B->ACD and C?D are supposed to hold. (a) What are all the keys in ABCD ? (b) Give example of a superkey in ABCD that is not a key. (c) Give example of a superkey in ABCD that is also a key. (d) Give example of a trivial functional dependency over ABCD.