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
[{'content': 'Which of the following is an example of proliferation signal inhibitor? \nSelect and explain. \nA. Tacrolimus, B. Sirolimus, C. Cyclosporine, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A new class of immunosuppressive agents called proliferation-signal inhibitors (PSIs) includes sirolimus (rapamycin) and its derivative everolimus. Ref: Katzung 11th edition Chapter 51.', 'role': 'assistant'}]