This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: D.O.C, Subject name: Pharmacology
[{'content': 'Which is not a favourable combination: \nSelect and explain. \nA. Amoxicillin and clavulanic acid, B. Ampicillin and cloxacillin, C. Piperacillin and tazobactam, D. Ampicillin and tazobactam', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. Ampicillin and cloxacillinAddition of beta lactamase inhibitors to penicillin will protect the penicillin from degradation. Beta lactamase inhibitors involve clavulanic acid, tazobactam and sulbactam. All combinations are correct except ampicillin and cloxacillin as cloxacillin is penicillinase resistant antibiotic.', 'role': 'assistant'}]