This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
Which of the following drugs is not a pa of the ' -Triple Therapy' immunosuppression for post-renai transplant patients ? 
Select and explain. 
A. Cyclosporine, B. Azathioprine, C. FK506, D. Prednisolone
C: FK506
Answer: C: FK506 
Explanation: All kidney transplants should receive maintenance immunosupressive therapies except identical twins The most frequently used combination is triple therapy- prednisolone Calcineurin inhibitors (Cyclosporine ) or tacrolimus previously called FK506. antimetabolite(Azathioprine or mycophenolate mofetil) TOR inhibitors can replace one of the last two agents (sirolimus or everolimus) Recently FDA approved drug -Belatacept Ref:Harrison 20 th edition pg no 2129