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': 'Radio activity was discovered by: \nSelect and explain. \nA. Marie curie, B. Pierre curie, C. Rutherford, D. Henri bequerel', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. Henri bequerel', 'role': 'assistant'}]