The word "odds" in Line 1 of Paragraph 1 means ______.

A．inform readers of Heller' s findings in his researches
B．persuade readers to get enough sleep at different ages
C．show readers the importance of getting enough sleep
D．tell readers how many hours of sleep they should get

A．the fact that many people cannot sleep and wake refreshed
B．the fact that the brain puts us to sleep when we are worn out
C．your sight, hearing, and attention are slow to alert you to dangers
D．increased risk of health problems or a serious, even deadly accident