What should you do?

You have a SQL Server 2012 database named Database1. You execute the following code:

You insert 3 million rows into Sales. You need to reduce the amount of time it takes to execute Proc1. What should you do?
A. Run the following: ALTER TABLE Sales ALTER COLUMN OrderDate datetime NOT NULL;
B. Change the WHERE clause to the following: WHERE OrderDate BETWEEN CAST(@date1,char(10)) AND CAST(@date2,char(10))
C. Remove the ORDER BY clause from the stored procedure.
D. Run the following:
DROP INDEX IX_Sales_OrderDate;
GO
CREATE INDEX IX_Sales_OrderDate ON Sales(OrderDate);
GO