There is no course of action which is productive to our interests.
If you honestly believe this, then the only rational move is to use your vote strategically to increase the chances of the viable candidate - who most closely aligns with your belief - getting elected. Effectively throwing your vote away on an unviable candidate increases the chances of the candidate less like you will win.
Play the game you're playing, not the one you wish you were.
And to answer your question, definitely 2. Although I believe i'm missing something.
You said earlier that even if progressives got someone through on the dem ticket, that they would still lose the general election because liberals would vote republican.
And you need it explained why writing someone in has even less of a shot?
You need to re-read my goal of writing someone in. Yes, getting someone decent through the primaries and hoping liberals support them in the general has less of a shot than demonstrating the Democrat party is non-viable in it's current state by writing in or voting 3rd party.