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': '90% of brain growth is achieved by the – \nSelect and explain. \nA. 2nd year, B. 3rd year, C. 5th year, D. 15th year', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The brain enlarges rapidly during the latter months of fetal life and early months of postnatal life.\nAt birth, the head size is about 65 to 70 percent of the expected head size in adults.\nIt reaches 90 percent of the adult head size by the age of 2 years.', 'role': 'assistant'}]