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: Pediatrics
[{'content': 'Which one of the following is not a feature of Phenylketonuria ? \nSelect and explain. \nA. Severe mental retardation, B. Reduced tendon reflexes, C. Enamel hypoplasia, D. Vomiting in early infancy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Reflexes are hyperactive.', 'role': 'assistant'}]