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': 'Amniocentesis is best diagnostic if done in.................weeks : \nSelect and explain. \nA. 10-Aug, B. 14-Dec, C. 16-18, D. 20-22', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 16-18', 'role': 'assistant'}]