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 for Fat cells is : \nSelect and explain. \nA. PAS, B. Alcian blue, C. Masson trichrome, D. Sudan IV', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Sudan IV', 'role': 'assistant'}]