You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version  3.5.  You create two user controls named UserCtrlA.ascx and UserCtrlB.ascx. The user controls postback to the server.  You create a new Web page that has the following ASPX code.  You need to ensure that the user control that is displayed meets the following requirements: ?¤It is recreated during postback  ?¤It retains its state.  Which method should you add to the Web page?（）

• A、
• B、
• C、
• D、