This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transplantation, Subject name: Surgery
The most commonly used drug in the immunosuppression of renal transplant patients is cyclosporine. A major side effect of this drug is: 
Select and explain. 
A. Pancytopenia, B. Constipation, C. Nephrotoxicity, D. Amenorrhea
C: Nephrotoxicity
Answer: C: Nephrotoxicity 
Explanation: Ironically, nephrotoxicity is the major problem associated with the use of cyclosporine. Despite this fact, it is the most commonly used immunosuppressive drug in renal transplant patients.