(25%) List the candidate keys and the highest normal forms for the following(2)relations. [a] R(A,B,C,D) {C->AD} [b] R(A,B,C,D) {C->A, A->BD} [c] R(A,B,C,D) {C->A, A->C, AC->B, B->D, D->B} [d] R(A,B,C,D) {С->А,

А->, АС->BD} [e] R(A,B,C,D) {C->B, BD->AC}