Forgive me, but how can you have tackling a "PASSER" by the face mask and NOT have Roughing the Passer? If the tackle was BEFORE he passed the ball, he's a "Runner" If he's actually thrown the ball, according to NFHS 2-32-11, "He continues to be a passer until the legal forward pass ends or until he moves to participate in the play."
The original question was about the quarterback, and never mentioned passing. On the other hand, it never mentioned that there was no pass, so the answers had to take into account the potential pass, too.
Yes, a test question would have been in the format of: "1st and 10 at A-20. A12 catches the snap and runs to A-18 where B55 tackles him by grasping and twisting the facemask. Where is the penalty enforced from?" But as this was just a play situation question on the forum, I think we don't need to be that pedantic in requiring the questions to be in an unambiguous form. We can always either attempt to answer all potential cases or ask for clarification.