When Researchers Studying Healthy Older Adults Looked to See Whether

When researchers studying healthy older adults looked to see whether there was a relationship between sleep efficiency and longevity, they found that

A) there was no relationship between sleep efficiency and longevity.
B) the most important factor was the time at which people went to bed, not sleep efficiency.
C) people who spent the highest percentage of bedtime asleep lived the longest.
D) those individuals who spent the highest percentage of bedtime asleep died at the earliest ages.