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': 'The increase in head circumference in 1st year of life is what percentage of head circumference at birth \nSelect and explain. \nA. 15%, B. 66%, C. 33%, D. 90%', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Head circumference at birth = 35cm\n↑ in HC in 1st 3 months = 2cm/month = 6cm\n↑\xa0 in HC in 4-6 months = 1cm/month = 3cm\n↑ in HC in 7-6 months = 0.5cm/month = 3cm\nBy 1st year, HC = 35+6+3+3 = 47cm\n↑ in HC = 47 - 35cm = 12cm\n% of\xa0↑ in HC in 1st year of life = 12/35\xa0× 100\xa0= 33%', 'role': 'assistant'}]