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: Social & Preventive Medicine
Birth length of the baby doubles at 
Select and explain. 
A. 6 months of age, B. 1 year of age, C. 2 years of age, D. 4 years of age
D: 4 years of age
Answer: D: 4 years of age 
Explanation: None