Which of the following observations provided the first evidence for an association between REM sleep and dreaming?
a.Dreaming is much more prevalent during NREM than first assumed.
b.Antidepressants greatly reduce or abolish REM sleep without affecting aspects of dream recall.
c.Kleitman and colleagues found that 80 percent of awakenings from REM sleep, but only 7 percent of awakenings from NREM sleep, led to dream recall.
d.Cortical lesions can abolish dreaming without affecting REM sleep.