This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diseases of the Aorta, Subject name: Medicine
[{'content': 'In coarctation of aorta, site of rib notching is? \nSelect and explain. \nA. Superior to rib, B. Inferior to rib, C. At sternum, D. At Vertebra', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. (b) Inferior to ribCauses of inferior rib notchingCauses of superior rib notching* Arterial: aortic coarctation, aortic thrombosis, pulmonary- oligemia/AV malformation, Blalock Taussig shunt, Tetralogy of fallot, absent pulmonary artery and pulmonary stenosis.* Venous: AV Malfomations of chest wall, superior vena cava or other central venous obstruction.* Neurogenic: Intercostal neuroma, Neurofibromatosis type 1, poliomyelitis.* Osseous: Hyperparathyroidism, Thalassemia* Poliomyelitis* Osteogenesis Imperfecta* Neurofibromatosis* Marfan's Syndrome* Collagen vascular disease* Hyperparathyroidism.", 'role': 'assistant'}]