Which of the following statements best describes the relationship between alcohol and sleep?
A. Alcohol may help initiate sleep, but it interrupts ongoing sleep and can be the cause of a sleep disorder.
B. Alcohol may help initiate sleep and enhance ongoing sleep, but it leads to addiction if used as a sleep aid.
C. Alcohol increases REM sleep.
D. Alcohol increases total sleep time in an effective manner, but continued use produces tolerance that negates this beneficial effect.