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': 'Investigation of choice in Diabetic mother with a doubtful abnormal fetus : \nSelect and explain. \nA. Sonography, B. Glycosylated haemoglobin, C. Amniocentesis, D. Chorionic villi biopsy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Sonography', 'role': 'assistant'}]