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': 'Minimal ascites can be best detected by – \nSelect and explain. \nA. USG, B. Plain X-ray abdomen, C. MRI, D. CT scan', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Minimal ascites is detected best by USG.', 'role': 'assistant'}]