(Choose 1 answer)
The functional dependency A -> B for relation schema R(A,B,C,D) implies that
A. no two tuples in R can have the same value for attribute B
B. no two tuples in R can have the same value for attribute A
C. any two tuples in R that have the same value for B must have the same value for A
D. any two tuples in R that have the same value for A must have the same value for B
ExiQ: 21
