Consider the relation scheme R(A,B,C,D,E,H) and the set of functional pendencies- AB,BCD,EC,DA hat are the candidate keys of R ? Consider a relation with schema R(A,B,C,D) and FD's ABC,CD, and DA. a) What are all the nontrivial FD's that follow from the given FD's? You should restrict yourself to FD's with single attributes on the right side. b) What are all the keys of R ? c) What are all the superkeys for R that are not keys