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: Surgery
[{'content': 'For aoic graft the best material available is - \nSelect and explain. \nA. Dacron, B. Aery, C. Vein, D. None', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Dacron", 'role': 'assistant'}]