A functional dependency, denoted by A $\rightarrow$B, between two sets of attributes A and B that are subsets of R, such that any two tuples t1 and t2 in r that have t1[A] = t2[A], they must also have t1[B] = t2[B].
This means that the values of the B component of a tuple in r depend on, or are determined by, the values of the A component;
We say that the values of the A component of a tuple uniquely (or functionally) determine the values of the B component. We say that there is a functional dependency from A to B, or that B is functionally dependent on A.
In functional dependency between two sets of attribute A and B
A $\rightarrow$B
A is determinant,B is dependent
ans should be C