单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You write the following code fragment. You need to ensure that the style is applied to all labels within the application. What should you do?（）

单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application contains a window that has two labels named First and Second. You need to display the label named First in blue. Which code fragment should you use?（）

单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You plan to create a window that has a layout as shown in the following exhibit. You need to define the code fragment to create the window layout. Which code fragment should you use?（）