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': 'The spleen contains about ...... % of the total blood volume - \nSelect and explain. \nA. 1, B. 2, C. 5, D. 7', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 2", 'role': 'assistant'}]