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': 'Best ultrasonic finding to detect IUGR is : \nSelect and explain. \nA. Abdominal circumference, B. Biparietal diameter, C. Femur length, D. Tibia length', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Abdominal circumference', 'role': 'assistant'}]