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: Surgery
[{'content': 'The drug of choice to prevent graft rejection in recipient is \nSelect and explain. \nA. Steroids, B. Vincristine, C. Cyclophosphamide, D. Methotrexate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]