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: Pharmacology
[{'content': 'Oral Contraceptive failure occurs in a patient on Rifampicin because of: \nSelect and explain. \nA. Rifampicin induce the metabolism of contraceptive, B. Rifampicin stimulates gonadotropin release from pituitary, C. Rifampicin decrease the secretion of progestin, D. Rifampicin antagonize the action of oral contraceptive', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]