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': 'All are alkylating agents, except ? \nSelect and explain. \nA. 5-FU, B. Melphalan, C. Cyclophosphamide, D. Chlorambucil', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 5 Fluorouracil", 'role': 'assistant'}]