ISRO | ISRO CS 2017 | Question 16

Consider the following query :

SELECT E.eno, COUNT(*)
FROM Employees E
GROUP BY E.eno

If an index on eno is available, the query can be answered by scanning only the index if

(A) the index is only hash and clustered
(B) the index is only B+tree and clustered
(C) index can be hash or B+ tree and clustered or non-clustered
(D) index can be hash or B+ tree and clustered

Answer: (C)
Explanation:
Quiz of this Question
Please comment below if you find anything wrong in the above post