Answer: E. Melatonin.
Explanation:
Melatonin is a kind of hormone which is not the derivative of aminoacids. It regulates and maintains the sleep and wake cycle in the human body. It is secreted by the pineal gland. It is used for the short term treatment for trouble in sleeping, and condition of jet lag. The concentration of release of the melatonin is more in dark and less in light. The production of melatonin decreases with that of age.
