This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Radiology
[{'content': 'Left cardiac border bulge can be seen in all, except - \nSelect and explain. \nA. Enlarged azygous vein, B. Left appendicular overgrowth, C. Coronary aery aneurysm, D. Pericardial defect', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Azygous vein is a Right sided structureand all others are left sided.It lies in thr angle between the right main bronchus and trachea and size is<10mm diameter on erect X-ray.', 'role': 'assistant'}]