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 position for chest X-ray to detect left pleural effusion is: \nSelect and explain. \nA. Left lateral, B. Supine, C. Left lateral decubitus, D. Right lateral decubitus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. Left lateral decubitus', 'role': 'assistant'}]