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 among the following is not a beta lactamase inhibitor ? \nSelect and explain. \nA. Sulbactam, B. Calvulanic acid, C. Piperacillin, D. None', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]