Ask HN: Choosing between 0.01 or 0.0001 percent success

Assume I'm working on two projects. Project A is a b2c piece of software that I designed to solve some itch. Assume also that I've managed to strike a deal to raise some money (500k-1M). Probability of success = (0.01)

Project B is a hard tech project, which I'm unqualified for, by a long way. Will take years and years of work, but will be the coolest thing I ever work on. Possible success rate = (0.0001)

Which do you pick and why?