Ask HN: If you had only 10^N dollars for a cause, what would you choose and why?

Rural EMS. Because in the US it's not funded except in a few places. Not only is it further to a hospital for, say, a heart attack but in some places you can't even get a first responder there in any reasonable time. If N were 5 or more I'd probably start some sort of foundation that focused on training and helping rural agencies apply for grant money. I doubt there is a reachable value of N that would solve the problem, there's no perfect world.