You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5.  All the content pages in the application use a single master page. The master page uses a static navigation menu to browse the site.  You need to ensure that the content pages can optionally replace the static navigation menu with their own menu controls. What should you do？ （）

• A、A
• B、B
• C、C
• D、D
• E、E
• F、F
• G、G
• H、H