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: Social & Preventive Medicine
[{'content': 'One TB infected person can infect how many people in 1 year? \nSelect and explain. \nA. 10, B. 30, C. 20, D. 5', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]