I would rule out C immediately, don't transfer it, but I wouldn't power it up personally.
When you receive mewtwo raids you can immediately evolve B and have one excellent attacker already. The 11 attack IV isn't too bad because there is not a terribly restricting breakpoint for Mewtwo.
How often do you have access to Tyranitar raids (are you in a big city and can you do one if you wanted to or do you need a lot of coordination?)