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': 'X-rays were discovered by - \nSelect and explain. \nA. Godfrey Hounsfield, B. Roentgen, C. Coulomb, D. Sievert', 'role': 'user'}, {'content': 'Answer: B \nExplanation: X-ray were discovered in 1895 by W.C. Roentgen.', 'role': 'assistant'}]