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？（）

A.In the Web.config file of the application，set the Theme attribute of the pages element to the name of the theme.

B.In the Web.config file of the application，set the StyleSheetThemeattribute of the pages element to the name of the theme.

C.Add a master page to the application. In the @Master directive，set the Theme attribute to the name of the theme.

D.Add a master page to the application. In the @Master directive，set the StyleSheetTheme attribute to the name of the theme.