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
Which of the following drug causes hemorrhagic  cystitis ? 
Select and explain. 
A. Cyclophosphamide, B. Cycloserine, C. Ciprofloxacin, D. Cyclosporine
A: Cyclophosphamide
Answer: A: Cyclophosphamide 
Explanation: None