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: Pathology
Nuchal fold thickness is used to dignose - 
Select and explain. 
A. Down's syndrome, B. Cri-du-chat sundrome, C. Durpan's syndrome, D. Paul-Bunnel sundrome
A: Down's syndrome
Answer: A: Down's syndrome 
Explanation: Ans. is 'a' i.e., Down's syndrome