Question ID:PT28 S3 Q19 Passage:On a certain day, nine scheduled flights on Swift Airlines were canceled.  Ordinarily, a cancellation is due to mechanical problems with the airplane scheduled for a certain flight.  However, since it is unlikely that Swift would have mechanical problems with more than one or two airplanes on a single day, some of the nine cancellations were probably due to something else. Stem:The argument depends on which one of the following assumptions? Correct Answer Choice:AChoice A:More than one or two airplanes were scheduled for the nine canceled flights. Choice B:Swift Airlines has fewer mechanical problems than do other airlines of the same size. Choice C:Each of the canceled flights would have been longer than the average flight on Swift Airlines. Choice D:Swift Airlines had never before canceled more than one or two scheduled flights on a single day. Choice E:All of the airplanes scheduled for the canceled flights are based at the same airport.