ISRO | ISRO CS 2015 | Question 20

Let R = (A, B, C, D, E, F) be a relation schema with the following dependencies C->F, E->A, EC->D, A->B. Which of the following is a key of R?
(A) CD
(B) EC
(C) AE
(D) AC

Answer: (B)
Explanation: Functional Dependencies of R = C->F, E->A, EC->D, A->B
Through the attributes C and E, we get all other attributes present in R.
So, EC is the key of R.
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