Research on Brain Regulation of Sleep Has, in General, Suggested

Multiple Choice

Research on brain regulation of sleep has, in general, suggested that

A) there is a single sleep-wakefulness center that uses serotonin.
B) there is a single sleep-wakefulness center that uses serotonin, norepinephrine, dopamine, and acetylcholine.
C) there are several brain areas involved in sleep but they all use serotonin.
D) several areas of the brain affect sleep, and they use serotonin, acetylcholine, norepinephrine, and dopamine.