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. You also need to ensure that the window contains a splitter line. 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. The application contains a window as shown in the following exhibit. You need to define a DockPanel control that fits the window. 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 that displays an image. You need to ensure that users can stretch and scale the image. Which control should you use?（）