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: Surgery
[{'content': 'Normal capacity of the renal pelvis is \nSelect and explain. \nA. 7 ml, B. 10 ml, C. 15 ml, D. 20 ml', 'role': 'user'}, {'content': 'Answer: A \nExplanation: • The average capacity of the renal pelvis is 4–8 ml.', 'role': 'assistant'}]