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': 'Best time for diagnosing fetal abnormalities by USG:September 2009 \nSelect and explain. \nA. 6-12 weeks of pregnancy, B. 13-19 weeks of pregnancy, C. 20-26 weeks of pregnancy, D. 27-32 weeks of pregnancy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: 13-19 weeks of pregnancy', 'role': 'assistant'}]