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: Dental
[{'content': 'A 2½ year old child with severe horizontal bone resorption and normal cementum is suffering from? \nSelect and explain. \nA. Hypophosphatasia, B. Precocious periodontosis, C. Down syndrome, D. Generalized periodontitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]