Which of the Following Is the Best Explanation for Why

Which of the following is the best explanation for why meditation might help Erika sleep more easily?

A) Meditation is associated with an increase in REM activity, which will make Erika feel more rested even when she is awake.
B) Meditation has been demonstrated to reduce physiological arousal, which may allow Erika to relax enough to fall sleep.
C) Meditation has very strong placebo effects, so even though it has no effect on the body Erika's expectations will allow her to fall asleep more easily.
D) Meditation is a state of consciousness that is nearly identical to slow-wave sleep, so it trains Erika's body to be ready for real sleep.