Inward then upward, C! I know somebody already answered, but I'm just confirming that answer is correct as I took a class in this sort of stuff! :)
I think you should stop and take a rest or a break. If the side stitch is really painful, then don't start running until it has stopped. Or you can walk it off so it might not get any more painful when you're resting.
Hello!
The correct answer is D. Warming up before every practice season.
I hope this helped!! If you need anything else, please feel free to let me know!! :-)