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 not used for lipids? \nSelect and explain. \nA. Oil red O, B. Congo red, C. Sudan III, D. Sudan black', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. (b) Congo redRef: Robbin's pathology 9th ed. /354Congo red is used for staining amyloid and not lipidsStains for Lipids* Oil red O* Sudan black* Sudan III and IV* Filipin* Schultz* Nile blue sulfate", 'role': 'assistant'}]