Cannot select function for Animation Event

Can anybody explain what I am doing wrong here? No functions are available in my Animation Event selector after I do the following:

1) I create an Animation (and animation controller) for my game object via Animation Window 2) I create a C# script and attach it to the game object that the Animator/Animation are attached to; this script includes Awake and a "SwapBody" function I want to call as the animation event 3) I right-click above the timeline to add an animation event, but no functions are available from the Function dropdown; just "(NoFunctionSelected)"

How do I make a function available to select for the Animation Event?