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
The drug which may inhibit P450 for warfarin is which one of the following: 
Select and explain. 
A. Cimetidine, B. Ethanol, C. Rifampicin, D. Procainamide
A: Cimetidine
Answer: A: Cimetidine 
Explanation: None