I think A makes the most sense 錠IMHO anybody who can make do with not-so-rock-solid is on master anyway, everybody else should probably stay on 2.10 anyway in this case.
OTOH, how about not doing a full release, but making an announcement that 2.12 won't come in favor of a better tested 3.0 and putting up "3.0 beta" ISOs, asking people to test the hell out of them (and master subsequently)?
--matthiasr