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: Radiology
[{'content': 'IoC to detect minimal ascites \nSelect and explain. \nA. USG, B. CT, C. MRI, D. PET', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ioc to detect minimal ascites\xa0→ USG.', 'role': 'assistant'}]