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
Mechanism of action of tacrolimus is ? 
Select and explain. 
A. Inhibition of transcription of IL 2, B. Inhibition of translation of IL 2, C. Inhibition of calcineurin, D. Both 'a' and 'c'
D: Both 'a' and 'c'
Answer: D: Both 'a' and 'c' 
Explanation: Ans. is 'd' i.e., Both 'a' and 'c'