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? （）

You use Microsoft .NET Framework 4 to create a Windows ...

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?（）

You use Microsoft .NET Framework 4 to create a Windows ...

单项选择题

You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. 
You need to ensure that the application meets the following requirements: 
Displays a menu that is specific to the control selected by the user. 
Displays the menu next to the control. 
Which control should you use? （）

You use Microsoft .NET Framework 4 to create a Windows ...

单项选择题

You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application that allows users to arrange images. 
You need to ensure that users can arrange child elements in a panel without affecting the size of the elements.  
You also need to ensure that child elements are oriented horizontally. 
Which control should you use?（）