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': 'Most crucial part of tuberculosis control programme is - \nSelect and explain. \nA. Contact tracing, B. BCG vaccination, C. Treatment of sputum positive cases, D. Treatment of X-ray positive cases', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The most powerful weapon in tuberculosis control is → case finding and lit.\nCases are defined by WHO as a patient whose sputum is positive for tubercle bacilli.', 'role': 'assistant'}]