Would be good to get the point of view of one of the legal eagles on this one.
I think it differs whether you are a private seller or a broker.
If you buy a car of a private vendor you have no recourse even if you buy a mini when you initially stated you need to have something in which you can haul your 5 strong off spring.
I would have thought something similar goes for buying aircraft.
My gut feeling says that C should be the right answer but in the nanny society we live it may well be B and that what Keef did may well have further exposed himself as it could be explained of an admission that he knew really that the guy was not suitable to fly it at the point of sale.
Who knows.
May have to go for judiciary review to get an answer. These things never have anything to do with common sense.
FD