3) Limit political donations to an amount almost anyone can make - $100. That would put the billionaire and the waitress on a level playing field.
I would rather ban donations altogether, with possibly the exemption of a 'fund' controlled by the electoral office, where anyone still feeling altruistic even if they can't bribe for policy, however the electoral office decdes how it splits the money between candidates, not the donor. The politicians don't even know who donated the money. Limiting donations doesn't work.