My (ex-)advisor is holding our paper hostage
If you really don't care about the paper then A seems ok as long as the paper isn't published without you.
But you could nudge the professor and then decide what you want to do. If you get unreasonable demands then you can back away which should prevent the paper being published (ethically, at least). But it is possible that your worst fears won't be realized and you have a simple way forward.
But I would save any ultimatum for a later round after you hear a response to a request to submit. You want to be the &quot;reasonable party&quot; in any conversation.