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: Gynaecology & Obstetrics
[{'content': "Trisomy 21 is also known as: September 2011 \nSelect and explain. \nA. Turner's syndrome, B. Klinefelter's syndrome, C. Down's syndrome, D. Alpo's syndrome", 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. C: Down's syndrome", 'role': 'assistant'}]