Which of them is certified as such?

Who really cares about whether something is "certified" UNIX? Certification is not some seal of quality. "Unix" is commonly understood to denote "functional" unix systems as well for lack of a more convenient term.

That os what the UNIX-like expression is for.

OS X would have been the only one certified. Even then I wouldn't call it a BSD per-se.

Oh, didn't realize you meant only certified Unices. I'll be on my way...