You work with a database named DB1， which is located on a SQL Server 2005 computer. You discover that a table scan on Table1 in DB1 causes a slow query. Table1 is a very large table that is used frequently. You ascertain that the query contains the following statement. SELECT col1， col2 FROM table1 WHERE col3 =  You need to provide maximum query performance. Table1 must remain available to users. What should you do？（）

• A、Update all statistics on Table1 in DB1.
• B、Use the CREATE STATISTICS statement in DB1 to create missing statistics on col3of Table1.
• C、Set the priority boost server option to 1.
• D、Execute the following statement.USE DB1GOCREATE INDEX index1 ON table1（col3）INCLUDE（col1， col2） WITH （ONLINE = ON）GO