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: Medicine
[{'content': 'Notching of ribs occurs in all, EXCEPT: \nSelect and explain. \nA. Coarctation of aoa, B. Neurofibromatosis, C. Hypothyroidism, D. Osteogenesis imperfecta', 'role': 'user'}, {'content': "Answer: C \nExplanation: Hypothyroidism is not associated with rib notching. Inferior rib notching is much commoner than superior notching. Causes of inferior rib notching are coarctation of aoa, tetralogy of Fallot, superior venacava obstruction, Blalock-Taussig shunt, neurofibromatosis. Causes of superior rib notching include, hyperparathyroidism, collagen vascular disease, rheumatoid ahritis, systemic lupus erythemoatosus, poliomyelitis, Marfan's syndrome, osteogenesis imperfecta. Ref: Differential Diagnosis in Conventional Radiology By Francis A. Burgener, Mati Kormano, Tomi Pudas, 2007, Page 310 ; Fundamentals of Diagnostic Radiology By William E. Brant, 2012, Page 519.", 'role': 'assistant'}]