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': 'Genetic disorders are diagnosed at 11 weeks of pregnancy by : \nSelect and explain. \nA. Chorionic villous biopsy, B. Amniocentesis, C. Endometrial biopsy, D. Placentography', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Chorionic villous biopsy', 'role': 'assistant'}]