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 not an alkylating agent? \nSelect and explain. \nA. Cyclophosphamide, B. Busulfan, C. 5-Fluorouracil, D. Melphalan', 'role': 'user'}, {'content': "Answer: C \nExplanation: 5- Fluorouracil' Repeat from AI1MS 09", 'role': 'assistant'}]