Few notes about the options in hand...

1. Sell itself to Intel, doesn't work as the competition authorities, either from the US or EU will prevent it. There is also an possibility that if Intel would become the only sole provider of x86 chips and have a monopoly on the markets, competition authorities could brake up the company.
2. Won't work if they don't get Microsoft behind their backs. Essentially Microsoft would need to make Windows hardware independent, which would benefit them as it would decrease the relative power of Intel, but then again transforming Windows and making all the work would take too long and take up too much money.
3. Again, without Windows they are dead in the water.

My own estimate is that they will make a complaint to the competition authorities of both the EU and the US on Intel levering its intellectual property to gain a complete market dominance. The EU has previously already ordered Microsoft to openly licence its protocols thus it could be probable that they could order Intel to openly license their intellectual property concerning x86 with a fair price. That is something that probably both Intel and AMD won't want, having a duopoly is much more profitable.