Hormonal regulating diurnal rhythm/sleep-wake cycle is
A) Thymosin
B) Glucagon
C) Melatonin
D) Oxytocin

Hint:A range of hormones differ across the 24-hour day including melatonin, cortisol, thyroid-stimulating hormone (TSH) which prolactin (PRL), and are strongly influenced by the circadian and sleep-wake cycles.

Complete answer:
In certain animal tissues, thymosins are small proteins present. They are called thymosins because they were originally isolated from the thymus, but in many other tissues, most are now understood to be present.

Thymosins have a wide variety of biological functions, and two thymosins, in particular alpha1 and β4, have theoretically substantial medicinal applications, both of which have already advanced from the laboratory to the clinic. Thymosins have been categorised as biological reaction regulators in relation to illnesses.

Glucagon, formed by alpha cells of the pancreas, is a peptide hormone. It acts to increase the bloodstream concentration of glucose and fatty acids and is known to be the body's primary catabolic hormone. To treat a variety of health problems, it is sometimes used as a medicine.

Melatonin is a hormone that controls the sleep-wake cycle, mainly produced by the pineal gland. It is also used as a dietary supplement for the short-term treatment of insomnia, such as jet lag or shift work, and is usually taken by mouth.

Oxytocin is both a hormone and a neuropeptide peptide. In the hypothalamus, it is usually developed and released by the posterior pituitary. It plays a role in the time after puberty, in social bonding, fertility, childbirth, and As a hormone in response to love and in labour, oxytocin is released into the bloodstream.

Hence the correct answer is option ‘C’.

Note: Sleep disturbances of the circadian rhythm are induced by desynchronization between internal sleep-wake cycles and the pattern of light-darkness. Usually, patients experience fatigue, extreme sleepiness during the day or both which usually turn out as the body clock realigns itself. Medical is the diagnosis. Based on the cause, treatment varies.