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？（）

You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. You create a Web page to display photos and captions. The caption of each photo in the database can be modified by using the application. You write the following code fragment：  
<asp：FormView DataSourceID="ObjectDataSource1" DataKeyNames="PhotoID" runat="server">  
<EditItemTemplate>  
<asp：TextBox Text=’<%# Bind（"Caption"） %>’ runat="server"/>  
<asp：Button Text="Update" CommandName="Update" runat="server"/>  
<asp：Button Text="Cancel" CommandName="Cancel" runat="server"/> 
</EditItemTemplate> 
<ItemTemplate>  
<asp：Label Text=’<%# Eval（"Caption"） %>’ runat="server" />  
<asp：Button Text="Edit" CommandName="Edit" runat="server"/>  
</ItemTemplate>  
</asp：FormView>   
When you access the Web page， the application throws an error. 
You need to ensure that the application successfully updates each caption and stores it in the database. 
What should you do？（）