Question ID:PT30 S2 Q9 Passage:A running track with a hard surface makes for greater running speed than a soft one, at least under dry conditions, because even though step length is shorter on a hard surface, the time the runner's foot remains in contact with the running surface is less with a hard surface. Stem:Which one of the following, if true, is evidence that the explanation given above is only a partial one? Correct Answer Choice:CChoice A:Dry running conditions can be guaranteed for indoor track races only. Choice B:In general, taller runners have greater average step length than shorter runners do. Choice C:Hard tracks enhance a runner's speed by making it easier for the runner to maintain a posture that minimizes wind resistance. Choice D:The tracks at which the world's fastest running times have been recorded are located well above sea level, where the air is relatively thin. Choice E:To remain in top condition, a soft track surface requires different maintenance procedures than does a hard one.