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: Pediatrics
[{'content': 'ACTH secretion is highest during – \nSelect and explain. \nA. Noon, B. Evening, C. Morning, D. Night', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Cortisol levels in blood are normally elevated at 8.00 AM and decrease to less than 50% by midnight.', 'role': 'assistant'}]