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: Surgery
[{'content': 'Best diagnostic aid in blunt trauma abdomen is - \nSelect and explain. \nA. CT scan, B. 4 quadrant aspiration, C. Peioneal lavage, D. Ultrasound', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Ultrasound", 'role': 'assistant'}]