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': 'If after 2 months of conventional antituberculous therapy, sputum smear examination is negative but culture is positive, it indicates - \nSelect and explain. \nA. Treatment failure, B. Transitional resistance, C. Resistant tuberculosis, D. category-II failure', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]