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 is an example of proliferation signal inhibitor? 
Select and explain. 
A. Tacrolimus, B. Sirolimus, C. Cyclosporine, D. None of the above
B: Sirolimus
Answer: B: Sirolimus 
Explanation: A new class of immunosuppressive agents called proliferation-signal inhibitors (PSIs) includes sirolimus (rapamycin) and its derivative everolimus. Ref: Katzung 11th edition Chapter 51.