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
[{'content': 'Which one of the following drugs can reduce the efficacy of low dose oral contraceptive pill : \nSelect and explain. \nA. Penicillin, B. Tetracycline, C. Ampicillin, D. Rifampicin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Rifampicin', 'role': 'assistant'}]