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: Gynaecology & Obstetrics
Which one of the following drugs can reduce the efficacy of low dose oral contraceptive pill : 
Select and explain. 
A. Penicillin, B. Tetracycline, C. Ampicillin, D. Rifampicin
D: Rifampicin
Answer: D: Rifampicin 
Explanation: Rifampicin