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': 'Sputum positive TB is \nSelect and explain. \nA. 2 out of 3 sputum sample +ve, B. 1 out of 2 sputum sample +ve, C. BACTEC +ve, D. Mantoux test positive', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]