You are a database developer. You plan to design a database solution by using SQL Server
2008. A database contains a table named Customer. The structure of the Customer table is
as shown in the following table. The solution uses the following stored procedure to return
customer details. Users report that the stored procedure takes a long time to execute. You
need to optimize the performance of the stored procedure. What should you do?

A.
Build a nonclustered index only on the country_id column.

B.
Recreate the primary key as a nonclustered unique index and build a clustered index on
the country_id column.

C.
Build a nonclustered index on the country_id column and use the INCLUDE clause to
include the customer_name column.

D.
Build a nonclustered index on the country_id, customer_name, and customer_id
columns.

Explanation: