The references on the first page of this thread refer to single pilot public transport ops.
Definitely European regs. and possibly ICAO (see previous) and answer (b) would be correct. I don't think single pilot ops is particularly ambiguous and it would be unusual, if not meaningless, to have dual crew in a 172.
Personal opinion though....
Last edited by FlyingGoat; 27th Dec 2010 at 22:38.