Mary Carskadon and Her Colleagues' Research on Adolescent Sleep Patterns

Mary Carskadon and her colleagues' research on adolescent sleep patterns found that

A) when given the opportunity, adolescents will sleep an average of 9 hours and 25 minutes a night.
B) adolescents' biological clocks undergo a shift as they get older so that older adolescents start to feel sleepy an hour earlier than younger adolescents.
C) younger adolescents tend to be sleepier during the day than older adolescents.
D) increased sleepiness in adolescents during the day was primarily due to academic work or social pressures.