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': 'Radioactivity was discovered by Becqueral in: \nSelect and explain. \nA. 1796, B. 1896, C. 1901, D. 1946', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. 1896', 'role': 'assistant'}]