Mr Reasoner Was Looking Out His Livingroom Window and Saw

Mr. Reasoner was looking out his livingroom window and saw his next-door neighbour, Jon Bon, trying to burn leaves. Bon threw gasoline on the damp leaves, and when he lit a match, there was an explosion that sent flames in every direction. Luckily, no one was around, and the flame that shot onto Reasoner's property caused no harm whatsoever. Reasoner was upset by this carelessness and sued Bon for negligence. Which of the following is the best argument for the defendant Bon?

A) He didn't owe the plaintiff a duty of care.
B) There were no damages suffered.
C) Reasoner had voluntarily assumed the risk.
D) He was not below the standard of care.
E) Reasoner was contributorily negligent.