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
[{'content': "Nuchal fold thickness is used to dignose - \nSelect and explain. \nA. Down's syndrome, B. Cri-du-chat sundrome, C. Durpan's syndrome, D. Paul-Bunnel sundrome", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Down's syndrome", 'role': 'assistant'}]