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': "OCP's are C/I in pts receiving: \nSelect and explain. \nA. Rifampicin, B. Ethambutol, C. Streptomycin, D. Pyrazinamide", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]