Conditional question

Hello,

Many kind thanks in advance to whoever can answer which of the following sentences is correct:

1. If your career plans don't work out, what would you do?

2. If your career plans didn't work out, what would you do?

3. If your career plans were to not work out, what would you do?

To me they all involve unreal future situations which go with the modal verb 'would'. However, I don't know which one is grammatically correct.

Thank you for your time and assistance.