Answer number one for me, with a very loose interpretation of "last resort." I would have to be pretty darn hungry, partly because I try to respect the religious beliefs of others and partly because butchering a human body would be disgusting, but I wouldn't wait until I was on the brink of starvation. And murder is always wrong, no matter how hungry you are. I guess I could sum that up by saying: human life is sacred; human flesh is meat.
As for my own mortal remains, I believe in recycling and re-using. When I die, put my healthy organs in the organ bank and my muscle tissue in the fridge. Oh, and use my skin for something too, like for binding a book. If I figure out what book I want it to be, I'll get suitable cover art tattooed on my back.