This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Aerial disorders, Subject name: Surgery
[{'content': 'Commonest cause of A-V fistulae is:- \nSelect and explain. \nA. Congenital, B. Traumatic, C. Surgical creation, D. Tumor erosion', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Aeriovenous Fistula (AVF) MC type of AVF: Congenital MC cause of acquired AVF: Penetrating trauma', 'role': 'assistant'}]