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': "Ascending aorta is involved in following types of dissecting aneurysm except \nSelect and explain. \nA. Stanford - B, B. Stanford - A, C. DeBakey's - type I, D. DeBakey's - type II", 'role': 'user'}, {'content': 'Answer: A \nExplanation: In\xa0Stanford - B, only descending aorta is involved.', 'role': 'assistant'}]