This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histo Pathology, Subject name: Pathology
[{'content': 'Stain used for pneumocystis carinii is:(1994) \nSelect and explain. \nA. Methylene blue, B. Gram stain, C. Hematoxylin and eosin, D. Methenamine silver', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans: dRef: Chandrasoma Taylor, 3rd ed, p. 347', 'role': 'assistant'}]