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': 'Best test to detect pneumoperitoneum is: \nSelect and explain. \nA. Chest X-ray, B. X-ray abdomen in supine position, C. X-ray abdomen in supine position, D. X-ray abdomen in lateral decubitus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: X-ray abdomen in lateral decubitus', 'role': 'assistant'}]