This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'Normal capacity of renal pelvis is \nSelect and explain. \nA. 7 ml, B. 12 ml, C. 15 ml, D. 20 ml', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The renal pelvis is roughly pyramidal, with the base facing the parenchyma and the apex funneling down into the ureter. It usually has a capacity of 3 to 10 mL of urine. ref : campbell - walsh urology 11th ed , chapter 42 , pg no : 973', 'role': 'assistant'}]