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: Microbiology
[{'content': 'Mycobacterium tuberculosis is differentiated from other atypical mycobacteria by- \nSelect and explain. \nA. Niacin test, B. AFB staining, C. PAS staining, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]