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': 'The method used for acid-fast staining - \nSelect and explain. \nA. Robertson’s method, B. Ziehl Neelsen, C. Silver impregnation method, D. Dark ground illumination', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Acid-fast staining\n\nAfter staining with aniline dye, acid-fast organisms resist decolourisation\xa0with acids.\nThe method most commonly used is modified Ziehl Neelsen.', 'role': 'assistant'}]