You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. The application contains a DataSourceControl named CategoriesDataSource that is bound to a Microsoft SQL Server 2005 table. The CategoryName column is the primary key of the table. You write the following code fragment in a FormView control： 01 02 Category： 03 04 ► 05 DataSourceID="CategoriesDataSource" 06 DataTextField="CategoryName" 07 DataValueField="CategoryID" 08 RunAt="Server" /> 09 10 You need to ensure that the changes made to the CategoryID field can be written to the database. Which code fragment should you insert at line 04？（）

A. SelectedValue=''
B. SelectedValue=''
C. SelectedValue=''
D. SelectedValue=''