问题：

[单选]

You are implementing an ASP.NET Web site. 
The site allows users to explicitly choose the display language for the site's Web pages. You create a Web page that contains a DropDownList named ddlLanguage, as shown in the following code segment.

The site contains localized resources for all page content that must be translated into the language that is selected by the user. You need to add code to ensure that the page displays content in the selected language if the user selects a language in the drop-down list. Which code segment should you use?（）

A . protected void SelectedLanguageChanged（object sender， EventArgs e） {Page.UICulture = ddlLanguage.SelectedValue；}
B . protected override void InitializeCulture（） {Page.UICulture = Request.Form["ddlLanguage"]；}
C . protected void Page_Load（object sender， EventArgs e） {Page.Culture = Request.Form["ddlLanguage"]；}
D . protected override void InitializeCulture（） {Page.Culture = ddlLanguage.SelectedValue；}