This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'Which is not a alkylating agent? \nSelect and explain. \nA. Cyclophosphamide, B. Chlorambucil, C. 5-FU, D. Melphalan', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 5-FU is an metabolite', 'role': 'assistant'}]