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
[{'content': 'ACTH level is higher during: \nSelect and explain. \nA. Early morning, B. Evening, C. Afternoon, D. Night', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Early morning(Ref: Ganong, 25th ed/p.366)ACTH and cortisol secretion is pulsatile with a characteristic circadian rhythm. It is high in the early morning and low in the evening75% of the daily production of ACTH & cortisol occurs between 4:00 AM and 10:00 AM', 'role': 'assistant'}]