Physician: The hormone melatonin has shown promise as a medication for sleep disorders when taken in synthesized form. Because the long-term side effects of synthetic melatonin are unknown, however, I cannot recommend its use at this time.
Patient: Your position is inconsistent with your usual practice. You prescribe many medications that you know have serious side effects, so concern about side effects cannot be the real reason you will not prescribe melatonin.
The patient's argument is flawed because it fails to consider that
(A)the side effects of synthetic melatonin might be different from those of naturally produced melatonin
(B)it is possible that the physician does not believe that melatonin has been conclusively shown to be effective
(C)sleep disorders, if left untreated, might lead to serious medical complications
(D)the side effects of a medication can take some time to manifest themselves
(E)known risks can be weighed against known benefits, but unknown risks cannot
题目分析：此题很简单，问的就是第二个人错在哪里了？文章反复在谈的就是这种治疗方法的副作用和以前某些治疗方法的副作用，围绕这个谈的就是E。A虽然谈到副作用，但谈的是自然的melatonin的副作用，范围不对，D情调一种medication的副作用，这个medication是哪种，不清楚，只有E明确说了是原文谈的那两种medication。
