You create a Web page named TestPage.aspx and a user control named contained in a file named TestUserControl.ascx.You need to dynamically add TestUserControl.ascx to TestPage.aspx. Which code segment should you use？（）

• A、protected void Page_Load（object sender， EventArgs e） { Control userControl=Page.LoadControl（"TestUserControl.ascx"）； Page.Form.Controls.Add（userControl）； }
• B、protected void Page_Load（object sender， EventArgs e） { Control userControl = Page.FindControl（"TestUserControl.ascx"）； Page.Form.Controls.Load（userControl）； }
• C、protected void Page_PreInit（object sender， EventArgs e） { Control userControl =Page.LoadControl（"TestUserControl.ascx"）；Page.Form.Controls.Add（userControl）； }
• D、protected void Page_PreInit（object sender， EventArgs e） { Control userControl = Page.FindControl（"TestUserControl.ascx"）； Page.Form.Controls.Load（userControl）； }