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': 'Mechanism of action of penicillins and cephalosporins is to inhibit : \nSelect and explain. \nA. Cell wall synthesis, B. Leakage from cell membrane, C. Protein synthesis, D. DNA gyrase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]