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': 'Which of the following is the most common feature of Aortitis on chest X-ray – \nSelect and explain. \nA. Calcification of ascending aorta, B. Calcification of descending aorta, C. Calcification of pulmonary artery, D. Focal oligemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The ascending aorta is a common site for calcification in aortitis, especially in syphilitic aortitis.', 'role': 'assistant'}]