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: March 2004 \nSelect and explain. \nA. USG, B. Glycosylated hemoglobin, C. Amniocentesis, D. Chorionic villous biopsy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A i.e. USG', 'role': 'assistant'}]