This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'The best approach to prevent congenital anomalies in infants of diabetic mothers is to? \nSelect and explain. \nA. Discontinue insulin and begin glyburide, B. Switch from an oral hypoglycemic agent to insulin until 36-week of gestation, C. Provide continuous insulin infusion during labor and delivery, D. Maintain periconceptional tight control of maternal blood glucose levels', 'role': 'user'}, {'content': 'Answer: D \nExplanation: .', 'role': 'assistant'}]