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 proper rate of rescue breathing in an adult is: \nSelect and explain. \nA. 4 times per min, B. 12 times per min, C. 20 times per min., D. 28 times per min', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]