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: Pathology
[{'content': 'Stain used to diagnose amyloidosis: September 2008 \nSelect and explain. \nA. Methylene blue, B. Acid fast stain, C. Rose bengal, D. Congo red', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: Congo red', 'role': 'assistant'}]