I'm pretty ignorant on the entire Caucasus, but I'd pick option #3 outlined in Marshall Murat's post. Clinging on to regions that don't want you is:
A) immoral
B) usually not worth it, anyway
Plus it seems rather far fetched to assume a country like Georgia could take and keep a region that wants to be part of Russia and wich Russia is willing to defend if necessary.

Does anyone know how the south Ossetians came to being Russian citizens?