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': 'Lecithin Sphingomyelin ratio in amniotic fluid is used to assess the maturity of : \nSelect and explain. \nA. Fetal liver, B. Fetal lung, C. Placenta, D. Fetal kidney', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Fetal lung', 'role': 'assistant'}]