Mentoring system means you only get the base 1250 of an A-rank job. Other bonuses do not stack with it. So you would be at 1500 exp.
Anyway, you're exam will consist of a 4,000 word story on character development. You may do what you want, just make it a good read. You may bring one other person along with you to help you progress the story, but they do not reduce your word count.
Post the link here when you're finished.