Final answer:
According to the activation-synthesis hypothesis, dreams are formed when the cortex of the brain combines random brain activity into stories and visual images during REM sleep.
Step-by-step explanation:
The answer to your question is c. activation synthesis hypothesis. According to the activation-synthesis hypothesis, the cortex of the brain combines random brain activity during REM sleep into stories and visual images that form dreams. This theory suggests that dreams are not intentionally created by the brain, but rather result from the brain's attempt to make sense of the neural activity that occurs during sleep. Alan Hobson, a neuroscientist, is credited with developing this theory.