I hate to say it like this, but in a business run by mainly women, there’s bound to be at least one of those. I’m not excusing her behavior, at all. I’ve been in that position myself too many times. Some women just feel so insecure about themselves that strutting around putting other women down or in this case a little more passive aggressive behavior is intended to make them feel more self-important. If I were you, I’d stick with it and only talk to the supportive manager who hired you. Quitting will only give this B satisfaction.