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': 'Average head circumference at birth is- \nSelect and explain. \nA. 35cm, B. 40cm, C. 45cm, D. 50 cm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Head circumference\n\nHead circumference is measured from the occipital protuberance to the supraorbital ridge of the forehead which is the maximum occipitofrontal diameter of the skull.\nThe head circumference in utero grow by 0∙5 cm in first 2 weeks, 0∙75 cm in 3rd week and after that 1 cm/week till birth.\nThe average head circumference at birth is 35 cm, which becomes 40 cm at 3 months, 43 cm at 6 months, 46 cm at 1 year, 48 cm at 2 years and 52 cm at 12 years.\nHead circumference is important to add to the diagnosis of neurological dysfunction and microcephaly.\nMicrocephaly is defined as a head circumference that measures more than three standard deviation below the mean for age.\nMacrocephaly is defined as head circumference that measure more than two standared deviation greater than mean for age.', 'role': 'assistant'}]