On your polling... the
Demolish buildings gives gold while abandoning city cost gold (based on population).
option seems to be winning.
I'd like to say that my problem with this is that it then just means you're enforcing the player to sell off everything first individually.
IF you included that only ONE building could be SOLD (for benefit) in a round, then I think we're cookin'. In fact, it wouldn't be such a bad idea to have a building tag that enabled more buildings could be sold in a round, like a demolition company or reclamation business building could add an extra building could be sold in a round (while perhaps as standard building tags, also giving a little gold for increased commerce and production for reclaimed materials, as the city would need this naturally for its ongoing natural updating of buildings.)
I suppose to do that we'd need to get deeper than I'm ready to so it could be a longterm project goal. Introducing a new tag for that would then pretty much demand that we included some 'destroy building' AI so the AI is able to make positive use of the system when needbe - which we do eventually need I think, as ways to help manage certain negatives that can build up too strong. Doing that without causing the turn times too much delay will be really complex. So again, longterm project goal.
But it would still be sufficient to simply set the amount of buildings that can be 'sold' in a round to a solid 1 only for now.