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 therapy to hypoxic tissues may be potentiated by the treatment with – \nSelect and explain. \nA. Mycostatin, B. Metronidazole, C. Methotrexate, D. Melphalan', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]