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
Cyclophosphamide is : 
Select and explain. 
A. Alkylating agent, B. Antitumor antibiotic, C. Monoclonal antibody, D. Antimetabolites
A: Alkylating agent
Answer: A: Alkylating agent 
Explanation: None