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: Pharmacology
[{'content': 'Which of the following is a radioprotector ? \nSelect and explain. \nA. Colony stimulating factor, B. Amifostine, C. Cisplatin, D. Methotrexate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]