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: Radiology
[{'content': 'Characteristic radiographic appearance of aoitis is: \nSelect and explain. \nA. Calcification of ascending aoa, B. Calcification of desecending aoa, C. Dilation of arch of aoa, D. Enlargement of left atrium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Calcification of ascending aoa', 'role': 'assistant'}]