15. Baking for winter holidays is tradition that may have a sound medical basis. In midwinter, when days are short, many people suffer from a specific type of seasonal depression caused by lack of sunlight. Carbohydrates, both sugars and starches, boost the brain's levels of serotonin, a neurotransmitter that improve the mood. In this respect, carbon hydrates act on the brain in the same way as some antidepressants, Thus, eating holiday cookies may provide an effective form of self-prescribed medication. Which one of the following can be properly inferred from the passage?

(A) Seasonal depression is one of the most easily treated forms of depression.

(B) Lack of sunlight lowers the level of serotonin in the brain. Page 6/6 Edited by Gmatstart (C) People are more likely to be depressed in midwinter than at other times of the year.

(D) Some antidepressants act by changing the brain's level of serotonin.

(E) Raising the level of neurotransmitters in the brain effectively relieves depression.

狂晕的是怎么感觉B,E,D都对啊。答案是D。