92. Baking for winter holidays is a 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 improves the mood. In this respect, carbohydrates 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.

(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.

答案是D。我觉得是B。

根据牛人的理论，infer题可以当作assumption题来做，就是对答案取非，如果取非后原文结论不成立，则为正确答案。

但是，B和D我都不知如何取非。请哪位牛人帮忙解答一下，明示我取非的方法和原则，感激不尽！

题目中给出，serotonin 可以让心情好，这不代表如果心情不好就是因为缺少serotonin 导致的。

from A--->B, we can't conclude that B--->A.