Probably none of the above,
A possibility you are missing is that Iran strikes a deal in a way that it gets to keep some token number of centrifuges operating while shutting down most of them.This way Iran would be able to save face while saving itself from mounting sanctions.This has happened in past and a lot of issues internationally have been dealt on same lines.
I think Iran would capitulate and this line of thought is derived from the fact that US has simply hit upon a jackpot of strategy in this bout of sanctions on Iran.Instead of going for Iran itself,Us is targeting it's business partners.Even though Iran could withstand Sanctions,it would be very hard for it's partners to do the same as they have significant exposure in the west.Even china was not able to resist the pressure and has cut it's demand for Iranian crude oil to half.
These sanctions also have an advantage that they need not be approved by security council.I see these set of sanctions being applied on all the countries antithetical to US in future.
