On A - if you're worried about extra utitlities, why not make them pay it themselves? Reduces your risk if they happen to leave the lights on all the time.
On B - my first time renting out a condo was to a new grad and this was basically her first place. She had no clue about looking after herself/living in a rented apartment. I was in the same boat as photon where things were good the first few inspections, but towards the end the true colours shined through. She never cleaned, did some un-approved renos, and tried to break the lease several months early (your B is 23 and it's her boyfriend...at that age and in a new situation, their circumstances can change pretty quickly).
I'd say C, then A.
|