You need to evaluate existing and potential clustered and non-clustered indexes that will improve performance

You administer a Microsoft SQL Server 2012 server. You plan to deploy new features to an
application.
You need to evaluate existing and potential clustered and non-clustered indexes that will improve
performance.
What should you do?

A.
Query the sys.dm_db_index_usage_stats DMV.

B.
Query the sys.dm_db_missing_index_details DMV.

C.
Use the Database Engine Tuning Advisor.

D.
Query the sys.dm_db_missing_index_columns DMV.

Explanation:
http://msdn.microsoft.com/en-us/library/ms174202.aspx