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 of the following drugs reduces efficacy of combined OCPs \nSelect and explain. \nA. Diazepam, B. Griseofluvin, C. Aspirin, D. Paracetamol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Griseofluvin is known to reduce efficacy of combined oral contraceptive pills.', 'role': 'assistant'}]