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': 'Oil red O staining is used for - \nSelect and explain. \nA. Frozen section, B. Glutaraldehyde fixed specimen, C. Alcohol fixed specimen, D. Formalin fixed specimen', 'role': 'user'}, {'content': 'Answer: A \nExplanation: . Frozen section', 'role': 'assistant'}]