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': "Posterior Scalloping of vertebra is seen in all except \nSelect and explain. \nA. Neurofibromatosis, B. Marfan's, C. Achondroplasia, D. Homocystinuria", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Fish mouth vertebra is seen in Homocystinuria.', 'role': 'assistant'}]