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': 'Which of the following antiepileptic does not cause OCP failure \nSelect and explain. \nA. Phenytoin, B. Valproate, C. Carbamazepine, D. Phenobarbitone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Because Sodium Valproate is an enzyme inhibitor, whereas other antiepileptics are enzyme inducers which can lead to OCP failure.', 'role': 'assistant'}]