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': "The best test in diabetic mother to diagnose baby's lung maturity : \nSelect and explain. \nA. Phosphatidyl inositol, B. Sphingomyelin/Lecithin ratio, C. Ultrasonography, D. None of the above", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Phosphatidyl inositol', 'role': 'assistant'}]