Consider a table that describes the customers :
Customers(custid, name, gender, rating)
The rating value is an integer in the range 1 to 5 and only two values (male and female) are recorded for gender. Consider the query “how many male customers have a rating of 5”? The best indexing mechanism appropriate for the query is

A

Linear hashing

B

Extendible hashing

C

B+ tree

D

Bit-mapped index