According to Researchers at University of Colorado Denver,what Was the Most

According to researchers at University of Colorado Denver,what was the most important factor in the high number of home runs at Coors Field?

A) The predominant summer wind direction is in favor of the batter.
B) The thin air allows the ball to fly further.
C) The lower temperatures help athletes not to overheat.
D) The thin air allows the batter to obtain better auditory cues about the pitch.