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': 'Investigation of choice for blunt trauma abdomen in unstable patient - \nSelect and explain. \nA. X-ray abdomen, B. USG, C. Diagnostic Peritoneal lavage (DPL), D. MRI', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]