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': 'Most common cause of Abdominal Aoic Aneurysm is: \nSelect and explain. \nA. Atherosclerosis, B. Trauma, C. Syphilis, D. Vasculitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The abdominal aoa is commonly afftected by atheroma by the process of atherosclerosis. This atheroma causes intimal weaking leading to aneurysm. so atherosclerosis is the leading cause for Abdominal Aoic Aneurysm. Ref: Encyclopedia of Hea Diseases By M. I. Gabriel Khan. 2006, Page 27', 'role': 'assistant'}]