This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth and development, Subject name: Pediatrics
[{'content': 'Mean head circumference at bih is? \nSelect and explain. \nA. 33-35 cm, B. 35-37 cm, C. 37-39 cm, D. 39-41 cm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Head circumference: Measured with a nonstretchable tape passing through the maximum point of occipital protuberance posteriorly and at a point just above the glabella anteriorly. If the head circumference is more than expected, always measure the both parents&; head circumference, for benign familial macrocephaly is common. At bih, it is around 34 cm. HC increases by 2 cm/month for the first 3 months, 1 cm/month for next three months and 0.5 cm per month for next 6 months. Ref: Ghai Essential Pediatrics, ninth edition. pg. no. 35.', 'role': 'assistant'}]