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
Bih length doubles by what age? 
Select and explain. 
A. 1 year, B. 2 years, C. 3 years, D. 4 years
D: 4 years
Answer: D: 4 years 
Explanation: 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.