You use Microsoft .NET Framework 4 to create a Windows Presentation Framework (WPF) application. You plan to create a custom control that contains four text input fields. Each of the text input fields within the control will contain a label. You need to ensure that the text input fields within the control can be validated by using a regular expression validator. Which class should you inherit from?
A.
TextBox
B.
TextElement
C.
UIElement
D.
UserControl