Someone gives two alternatives to choose between then the next person have to choose one of them, which one you would choose if you had to, then this person gives two new alternatives.
Fun huh?!
Ok I'll start:
being alone on an island for the rest of your life or being a member of the nazi mob for a limited amount of years?
I don't think this exists for humans yet, unfortunately - but what I think would be the healthiest mattress (and virtually free of dust-mites, even bed-bugs which inflict some homes recently) for humans would be the same as the healthiest for pets...