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: Medicine
[{'content': 'Which of the following true about resistant - TBa) Sputum smear is positive after 5 monthb) Culture is positive after 3 months c) Clinical deteriorationd) Active disease in chest X-ray \nSelect and explain. \nA. abd, B. bcd, C. abc, D. ab', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]