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
Which of the following is not a feature of hypothyroidism? 
Select and explain. 
A. Mental retardation, B. Large head, C. Microcephaly, D. Calf muscle hypertrophy
C: Microcephaly
Answer: C: Microcephaly 
Explanation: Hypothyroidism characterized by open and widened fontanelle results in large head and mental retardation