This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Pathology
[{'content': 'Stain not used for lipid - \nSelect and explain. \nA. Oil red, B. Congo red, C. Sudan III, D. Sudan black', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Special stains for fat: Frozen sections stained with Sudan IV or Oil Red-O give an orange-red color to the fat. Osmic acid gives a black color.', 'role': 'assistant'}]