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': 'Notching of ribs on X-ray is seen in: \nSelect and explain. \nA. PDA, B. ASD, C. Ebstein Sanomaly, D. Coarctation of aoa', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. Coarctation of aoa', 'role': 'assistant'}]