The American "first past the post" voting system is (for lack of a better term) stupid. It leads to exactly the dilemma you talk about
: "Should I vote for the person I actually
want to get in, or the most promising candidate opposed to the person I don't
want to get in?".
In Australia, we have a voting system where you specify preferences
: You vote for the candidate you want, then specify who your vote should 'trickle down to' if that candidate doesn't receive enough votes to be elected. It's not perfect, but it's a lot
fairer than 'first past the post'.
As Steve has said: If you don't like any of the options, open yourself to finding a "third alternative option".
In this case, that alternative option might well be to realise that the voting system itself is broken and do what you can to change it.
P.S. You forgot the "Become the candidate you want to see in the world" option too.