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': 'Rib notching is seen in all the following except: \nSelect and explain. \nA. Blalock-Taussing shunt, B. Coarctation of the aoa, C. TVC obstruction, D. None', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. None', 'role': 'assistant'}]