According to the consolidation theory that explains the benefits of sleep, researchers have found that

a. adolescents tend to spend more time in non-REM sleep because that is when growth hormones are released.
b. older adults tend to spend more time in non-REM sleep because they process information more slowly than young adults.
c. students tend to spend more time in REM sleep during exam periods because they are processing a lot of information.
d. infants tend to spend less time in REM sleep because they don't spend a lot of time awake, during which they would receive visual stimulation.