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': "A 'Case' in T is defined as - \nSelect and explain. \nA. X-ray positive, B. Culture positive, C. Sputum AFB positive, D. Tuberculosis positive", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]