Why do I only have the option to be crowned by an unimportant priest? I'm a feudal Catholic king. When I choose the Coronation decision, the only options are being crowned by a common priest or cancelling the process.

Why can't I be crowned by the Pope? I don't have the intermediate option either, but I guess that's because there are no Prince-Bishops within my realm. Does it have to do with the Pope not being an available option?