You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5.  The application contains two HTML pages named ErrorPage.htm and PageNotFound.htm.   You need to ensure that the following requirements are met： when the user requests a page that does not exist， the PageNotFound.htm page is displayed.  when any other error occurs， the ErrorPage.htm page is displayed.   Which section should you add to the Web.config file？（）

• A、A
• B、B
• C、C
• D、D