This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pediatrics
[{'content': 'Clinical features of "hypothyroidism" in a newborn are all except: \nSelect and explain. \nA. Sluggishness +++, B. Large tongue, C. Large posterior fontanel, D. Mental retardation', 'role': 'user'}, {'content': "Answer: D \nExplanation: d. Mental retardation(Ref: Nelson's 20/e p 2669-2773, Ghai 8/e p 516-521)Mental retardation (Intellectual disability) develops by 3-6 months of age (not in neonatal period).", 'role': 'assistant'}]