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': 'The most common cause of acquired arteriovenous fistula is- \nSelect and explain. \nA. Bacterial infection, B. Fungal infection, C. Blunt trauma, D. Penetrating trauma', 'role': 'user'}, {'content': 'Answer: D \nExplanation: "Penetrating injuries are the most common cause, but fistulas are sometimes seen after blunt trauma" - CSDT', 'role': 'assistant'}]