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': 'Radiation exposure in an IOPA radiograph is ? \nSelect and explain. \nA. 200 micro Sieverts, B. 26 micro Sieverts, C. 5000 micro Sieverts, D. 5 micro Sieverts', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]