31.考量relation R = {A, B, C, D, E, F, G, H, I, J }具有一組功能相依性FD={{A, B}→{C}, {B, D}→{E, F}, {A, D}→{G, H}, {A}→{I}, {H}→{J}},則R之key為何?
(A) {A, B, C}
(B) {A, B, D}
(C) {A, B, E}
(D) {A, B, F}
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統計: A(8), B(61), C(8), D(2), E(0) #1325634
統計: A(8), B(61), C(8), D(2), E(0) #1325634