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: Pathology
[{'content': 'Which of the following is the most common site for syphilitic aneurysm \nSelect and explain. \nA. Descending aorta, B. Ascending aorta, C. Internal carotid artery, D. External carotid artery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Syphilitic aneurysm most frequently occurs in ascending aorta. Syphilitic aneurysm occurs in tertiary stage of syphilis.', 'role': 'assistant'}]