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': 'Unit of one dose of radiation absorbed is: \nSelect and explain. \nA. Grey, B. Roentgen, C. Curie, D. Bequerrel', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Grey', 'role': 'assistant'}]