This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacokinetics, Subject name: Pharmacology
Effect of oral contraceptive pills is inhibited by : 
Select and explain. 
A. Rifampicin, B. Cimetidine, C. Ethambutol, D. Propranolol
A: Rifampicin
Answer: A: Rifampicin 
Explanation: Ans. is 'a' i.e. Rifampicin