70-511 Question #107: Real Exam Question with Answer & Explanation

You are developing a Windows Presentation Foundation (WPF) application. The WPF window contains a ListBox control that displays a list of customer names and genders. You add the following markup segment to the application. (Line numbers are included for reference only.) The WPF window renders the list of customers with empty Gender values. You need to convert the null values for Gender to the following string: "Gender Not Specified". Which binding attribute should you add at line 08?