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
Sterile hemorrhagic cystitis is caused by : 
Select and explain. 
A. Busulfan, B. Ketoprofen, C. Methicillin, D. Cyclophosphamide
D: Cyclophosphamide
Answer: D: Cyclophosphamide 
Explanation: None