> Now there are four options WPF, WinForms, UWP and Xamarin. Ok...Why are there four options? What are the differences? Are one or more of them about to be deprecated?

You're most likely best of picking WinForms. It's old school, but it seems like it's going to be the one Microsoft will have the hardest time killing.

WPF, UWP and Xamarin fine frameworks, but for the 0.9X developer who just want a window, with a few input and some buttons, you can't beat WinForms in ease of use.

My reasoning is that most of the developers who saw WPF and jumped on that, are the same who will more easily jump to UWP, and from there to what ever comes next. The WinForms developer aren't moving.