This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth, Subject name: Pediatrics
[{'content': 'Bih length doubles by what age? \nSelect and explain. \nA. 1 year, B. 2 years, C. 3 years, D. 4 years', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Bih length doubles by 4- 4 1/2 yrs of age Age Bih 1 year 2 year 4 year 12 year Height 50 cm 75 cm 90 cm 100 cm 150 cm Length of child increases by 50% in 1st year.', 'role': 'assistant'}]