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
True about azathioprine is : 
Select and explain. 
A. It has more anti tumor effect than immunosuppressant effect, B. It is not a prodrug, C. It selectively affects differentiation of T cells, D. It is a pyrimidine antimetabolite
C: It selectively affects differentiation of T cells
Answer: C: It selectively affects differentiation of T cells 
Explanation: None