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': 'Methicillin-resistant staphylococci do not respond to β–lactam antibiotics because : \nSelect and explain. \nA. They produce a β–lactamase which destroys methicillin and related drugs, B. They elaborate an amidase which destroys methicillin and related drugs, C. They have acquired penicillin binding protein which has low affinity for β-lactam antibiotics, D. They are less permeable to β-lactam antibiotics', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Resistance to most penicillins is due to elaboration of beta-lactamase.\nMethicillin is most resistant penicillin to β-lactamase.\nStaphylococcus aureus develops resistance to methicillin by the acquisition of altered penicillin-binding proteins.', 'role': 'assistant'}]