An exact-match query is:

A. Where a record is returned if its relevant key value falls within a specified range

B. Another name for any database query that returns a key value

C. Where a record is returned if its unique identifier matches the search value

D. A way of efficiently locating the records in a database

C. Where a record is returned if its unique identifier matches the search value

Explanation:

Exact match is a Google keyword match type that allows you show your adverts when searcher type the exact word or phrase you are bidding on. An exact match query will always return records that matches what is being searched on.