Answer:
The correct answer is Faustus is frightened of religious symbols.
Step-by-step explanation:
Faustus feels threatened by the Pope when crossing himself, and threatens him by warning not to do it again.
The Pope does it again, and Faustus gives him a second threat, telling him not to do it a third time.
Apparently, Faustus only manages to threaten the Pope to stop doing that because it causes him terror, but he can do nothing more than try to scare him, and see if he gets him to stop.