Consider the relation R = {A, B, C, D, E, F, G, H, I, J} and the set of functional dependencies F = {{H, D--A, D-{E, F, G},{H, D, B}-{C, J), H-{I, J}, A-{B, C}}. What is the key for R? Select one: O a. {B, D} O b. (H, D, B} O c. {H, D, A) O d. {H, D)