This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and Reproduction, Subject name: Physiology
Melatonin is produced by- 
Select and explain. 
A. Pituitary, B. Pineal gland, C. Hypothalamus, D. Thalamus
B: Pineal gland
Answer: B: Pineal gland 
Explanation: Ans. is 'b' i.e., Pineal gland * Melatonin ia a hormone secreted by pineal gland.* It is involved in sleep-wake cycle.