Critical Reasoning

Q114
Normally, the pineal gland governs a person's sleep-wake cycle by secreting melatonin in response to the daily cycle of light and darkness as detected by the eye. Nonetheless, many people who are totally blind due to lesions in the visual cortex of the brain easily maintain a 24-hour sleep-wake cycle. So the neural pathway by but which the pineal glands receives information from the eye probably does not pass through the visual cortex.
For purposes of evaluating the argument it would be most useful to establish which of the following?
A.Whether melatonin supplements help people who have difficulty maintaining a 24-hour sleep cycle to establish such a pattern.
B.Whether melatonin level of most totally blind people who successfully maintain a 24-hour sleep-wake cycle change in response to changes in exposure to light and darkness.
C.Whether melatonin is the only substance secreted by the pineal gland.
D.Whether most people who do not have a 24-hpur sleep-wake cycle nevertheless have a cycle of consistent duration.
E.Whether there are any people with normal vision whose melatonin levels respond abnormally to periods of light and darkness.

Help needed! How to handle these kind of questions in CR?
Thanks!

Option B is correct by process of elimination

a) we are not asked whether melatonin is effective or not, we are asked about it's path
c)we are not concerned about different type of secretions by pineal gland
d)Here the option is niether related to Melatonin nor differentiaitng blind people and normal people
e) we won't get any clue regarding how the information passes from the eye to the gland even if the melatonin level in normal vision people responds abnormally.
B ) if the answer is yes, then we can say melatonin in blind people is affected by Light and Darkness
if the answe is no, then we can say melatonin is not affected by light and darkness
By evaluating option B we will get a clear Yes/No : So this option is correct

Correct me if my logic is wrong