You modify an existing Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. You add a theme to the ASP.NET application. You need to apply the theme to override any settings of individual controls. What should you do？（）
- AIn the Web.config file of the application，set the Theme attribute of the pages element to the name of the theme.
- BIn the Web.config file of the application，set the StyleSheetThemeattribute of the pages element to the name of the theme.
- CAdd a master page to the application. In the @Master directive，set the Theme attribute to the name of the theme.
- DAdd a master page to the application. In the @Master directive，set the StyleSheetTheme attribute to the name of the theme.