You work as a Web Developer at Certkiller.com. You are in the process of creating a Webapplication using Microsoft ASP.NET 3.5. The following markup should be added to a page：   The Question control is a custom server control that originates from the WebControl. This controldoes not implement any interfaces. The following characteristics are applied to the control’s class：ToolboxData， Designer， and DefaultProperty. You have to make sure that the Question control is able to participate in server-side validation onthis page. What should you do？（）

• A、You should consider modifying the Question control’s class in order to implement IValidator.
• B、You should consider setting the ValidationGroup property of the RequiredFieldValidator controlto UserControl.
• C、You should apply the ValidationProperty feature to the Question control’s class.
• D、You should consider setting the InitialValue property of the RequiredFieldValidator control to anempty string.