You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. You plan to add a custom parameter in the SqlDataSource control. You write the following code fragment：                       You write the following code segment to create a custom parameter class：   public class DayParameter ： Parameter { } You need to ensure that the custom parameter returns the current date and time. Which code segment should you add to the DayParameter class？ （）

• A、A
• B、B
• C、C
• D、D