This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamentals in Radiology, Subject name: Radiology
[{'content': "Grid is a device used for - \nSelect and explain. \nA. Reducing scattered radiation, B. Reducing patient's exposure time, C. Reducing the contrast of the X-ray, D. All of the above", 'role': 'user'}, {'content': 'Answer: A \nExplanation: X ray grid ensures the contrast of image on X ray film. X ray grid absorbs the scattered xrays and filters out radiations', 'role': 'assistant'}]