單項選擇題

You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application.  
The application displays a list of books. 
You write the following code fragment. (Line numbers are included for reference only.)

You need to ensure that book titles that are out of stock appear in red.
Which code fragment should you insert at line 12?()

A.
B.
C.
D.

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