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': 'Grid" is a device which is used for: \nSelect and explain. \nA. Reducing scattered radiation, B. Reducing patients exposure time, C. Reducing the contrast of the X-ray, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Reducing scattered radiation', 'role': 'assistant'}]