This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
[{'content': 'Bacitracin acts on \nSelect and explain. \nA. Cell wall, B. Cell membrane, C. Nucleic acid, D. Ribosome', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref Katzung 10/e p 741 Bacitracin acts by inhibiting the synthesis of cell wall Other polypeptide antibiotics like Polymyxin B, colistin and tyrothricin act by affecting membranes', 'role': 'assistant'}]