Which of the Following Statements Best Explains Why We Get

Multiple Choice

Which of the following statements best explains why we get tired at night?

A) There is no physical reason why; we have been psychologically and socially conditioned to feel tired and sleep at night.
B) Our body temperature and heart rate drop at night,causing us to feel tired.
C) Our pineal gland stops producing melatonin at night,causing us to feel tired.
D) There is a nucleus in the brain that is sensitive to light and tells us when to wake and sleep.