You are creating an ASP.NET Web site.  The site has a master page named Custom.master.  The code-behind file for Custom.master contains the following code segment.   You create a new ASP.NET page and specify Custom.master as its master page. You add a Label control named lblRegion to the new page.  You need to display the value of the master page’s Region property in lblRegion. What should you do？ （）

• A、Add the following code segment to the Page_Load method of the page code-behind file. CustomMaster custom = this.Parent as CustomMaster； lblRegion.Text = custom.Region；
• B、Add the following code segment to the Page_Load method of the page code-behind file. CustomMaster custom = this.Master as CustomMaster； lblRegion.Text = custom.Region；
• C、Add the following code segment to the Page_Load method of the Custom.Master.cs code-behind file. Label lblRegion = Page.FindControl（"lblRegion"） as Label； lblRegion.Text = this.Region；
• D、Add the following code segment to the Page_Load method of the Custom.Master.cs code-behind file. Label lblRegion = Master.FindControl（"lblRegion"） as Label； lblRegion.Text = this.Region；