【单选题】

Which of the following statements is true according to the passage?

A.20% of all high school students fall asleep in school during school time.
B. Most students go to bed at 9:O0 p.m. and wake up at 6:00 a.m. to get a good nine hours of sleep before 11:00 in the evening.
C. People are likely to fall asleep before 11:00 in the evening.
D. Most high school students need at least 9 hours of sleep a day.