阅读下列短文, 从给的四个选项 (A、B、C和D) 中, 选出最佳选项。
(2013·沈阳市二模，B)
A recent research shows that the “short sleepers” had been more or less average in their sleep needs until the men were in their teens. But at the age of 15 or so, the men voluntarily began cutting down their nightly sleep time because of pressures from school, work, and other activities. These men tended to view their nightly periods of unconsciousness as interruptions in their daily routines.
