You are implementing an ASP.NET application that includes a page named TestPage.aspx. TestPage.aspx uses a master page named TestMaster.master. You add the following code to the TestPage.aspx code-behind file to read a TestMaster.master public property named CityName. protected void Page_Load（object sender， EventArgs e） { string s = Master.CityName； } You need to ensure that TestPage.aspx can access the CityName property. What should you do？（）

Add the following directive to TestPage.aspx.
B. Add the following directive to TestPage.aspx.
C. Set the Strict attribute in the @ Master directive of the TestMaster.master page to true.
D. Set the Explicit attribute in the @ Master directive of the TestMaster.master page to true.%@>%@>