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 aEUR' \nSelect and explain. \nA. 5-FU, B. Melphalan, C. Cyclophosphamide, D. Chlorambucil", 'role': 'user'}, {'content': 'Answer: A \nExplanation: 5 Fluorouracil Repeat from May 10 Q no.68', 'role': 'assistant'}]