You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application.  
The application contains a composite user control that includes a TextBox control named txtInput.  
The user control will be hosted in a window and will have handlers for the text-changed event of txtInput.  
You need to ensure that the application meets the following requirements: 
Creates a text-changed event handler named Audit_TextChanged for the txtInput control. 
Executes Audit_TextChanged even when specific handlers mark the event as handled. 
Which code segment should you add to the constructor of the user control?（）

A.txtInput.TextChanged+=Audit_TextChanged;
B.AddHandler(TextBox.TextChangedEvent, new  RoutedEventHandler(Audit_TextChanged), true);
C.EventManager.RegisterClassHandler(typeof(TextBox),  TextBox.TextChangedEvent, new  RoutedEventHandler(Audit_TextChanged), true);
D. EventManager.RegisterClassHandler(typeof(TextBox),  TextBox.TextChangedEvent, new  RoutedEventHandler (Audit_TextChanged), false);