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 ButtonHandler method is not executed when the user clicks the CancelButton button. 
Which code segment should you add to the code-behind file?（）
 

A. Write the following code segment in the button onclick event.     System.Media.    SoundPlayer player = new System.Media.    SoundPlayer(SoundFilePath); player.play();
B. Write the following code segment in the button onclick event.    MediaPlayer player = new MediaPlayer();     player.Open(new URI(SoundFilePath),    UriKind.Relative)); player.play();
C. Use the following code segment from the PlaySound()    Win32 API function and call the PlaySound function in the button onclick event.    [sysimport(dll="winmm.dll")]     public static extern long PlaySound(String SoundFilePath, long hModule, long dwFlags);
D. Reference the Microsoft.DirectX Dynamic Link Libraries.     Use the following code segment in the button onclick event.     Audio song = new Song(SoundFilePath);     song.CurrentPosition = song.Duration; song.Play();

A. lbDetails.ItemsPanel.FindName("detail",lbDetails);
B. var tmpl = (ControlTemplate)FindResource("detail");    lbDetails.Template = tmpl; 
C. var tmpl = (DataTemplate)FindName("detail");    lbDetails.ItemTemplate = tmpl;
D. var tmpl = (DataTemplate)FindResource("detail");    lbDetails.ItemTemplate=tmpl;

A.
B.
C.
D.