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': 'Bile is concentrated in the gall bladder to _________ times \nSelect and explain. \nA. 10-May, B. 15-Oct, C. 20-30, D. 40-50', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]