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': 'The method of choice of tuberculosis detection mass screening is \nSelect and explain. \nA. Tuberculin test, B. Sputum smear examination by direct microscopy, C. Mass Miniature Radiography (MMR), D. Sputum culture', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]