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: Radiology
All are radiosensitizer except – 
Select and explain. 
A. 5-Fu, B. BUDR, C. Cyclophosphamide, D. Hydroxyrea
C: Cyclophosphamide
Answer: C: Cyclophosphamide 
Explanation: None