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': 'By WHO best criteria for TB diagnosis is \nSelect and explain. \nA. Sputum + ve, B. Chest pain, C. Cough – 3 weeks, D. X-ray finding', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]