Normally, the pineal gland governs a person’ssleep-wake cycle by secreting melatonin in response to the daily cycle of lightand darkness as detected by the eye. Nonetheless, many people who are totallyblind due to lesions in the visual cortex of the brain easily maintain a24-hour sleep-wake cycle. So the neural pathway by which the pineal glandreceives information from the eye probably does not pass through the visualcortex.

　　正常情况下，松果腺控制着一个人的睡眠-觉醒循环，通过分泌褪黑激素应对眼睛所察觉到的明暗循环。然而，很多由于大脑中视觉皮层受到伤害而导致完全失明的人却很容易维持24小时的睡眠-觉醒循环。所以，松果腺从眼睛接受信息的神经通路很有可能不通过大脑中的视觉皮层。

　　For purposes of evaluating the argument itwould be most useful to establish which of the following?

　　为了评价上述论证，建立下列哪项将会最有用?

　　(A) Whether melatonin supplements help peoplewho have difficulty maintaining a 24-hour sleep cycle to establish such apattern

　　是否褪黑激素的补充帮助那些很难维持24小时睡眠循环的人建立这样的模式?

　　(B) Whether the melatonin levels of mosttotally blind people who successfully maintain a 24-hour sleep-wake cyclechange in response to changes in exposure to light and darkness

　　是否大部分成功维持24小时睡眠-觉醒循环的盲人的褪黑激素的水平会随着明暗产生变化?

　　(C) Whether melatonin is the only substancesecreted by the pineal gland

　　是否褪黑激素是松果腺产生的唯一物质?

　　(D) Whether most people who do not have a24-hour sleep-wake cycle nevertheless have a cycle of consistent duration

　　是否大部分没有这样循环的人但拥有一个恒定持续期的循环?

　　(E) Whether there are any people with normalvision whose melatonin levels respond abnormally to periods of light anddarkness

　　是否有任何一个拥有正常视觉的人，他的褪黑激素的水平会随着明暗不正常的变化?