Enhance application behavior and style based on browser feature detection

You are creating a different view for each of several different browsers/devices, such as Home.iemobile.cshtml and Home.IPad.cshtml. What is the best way to implement it so your application knows to look for the specific views?

You don’t have to do anything. The framework automatically handles browser/device detection by reading the new extensions on the views.
Add a new DisplayModeProvider for each of the special view types you want to support.
Use the viewport <meta> tag.
Put logic into each action to select the appropriate view based on information in the request.