C versus D

Hi Medas, I think that C is stating that more actual flight time will lead to fewer crashes, while D is saying that lack of actual flight time relates to error. C is much stronger, while D tells us only that flight time contributes to error. Since we are looking for something the author must believe, D is correct since if there were no relationship between flight time and error then the argument would make no sense. C is not necessarily something the author thinks, since even if we do more training, the overall number of crashes could increase for some other reason, like a software flaw or war.