This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Trauma, Subject name: Surgery
[{'content': 'In polytrauma with blunt abdominal injury, the first investigation to evaluate his abdomen is \nSelect and explain. \nA. USG, B. CT Scan, C. Complete Hemogram, D. Abdominal X-ray', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a)USG is the first investigation to evaluate abdomen in bunt trauma.Ref. Schwartz 10th/e p. 179 and 9th/e p. 151; Washington Manual of Surgery 5th/e p. 373 * CT scan is the best investigation.', 'role': 'assistant'}]