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
Risk of Down's syndrome in Elderly (>35 years) 
Select and explain. 
A. 1% - 2%, B. 1% - 4%, C. 2% - 4%, D. 1% - 5%
B: 1% - 4%
Answer: B: 1% - 4% 
Explanation: Risk of Down's syndrome in Elderly (>35 Years) is 1% - 4%.