This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'One of the following is not true about melatonin: \nSelect and explain. \nA. Induces sleep, B. Used in treatment of jet lag syndrome, C. Is secreted by pituitary, D. Is a pineal hormone', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]