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': 'The mechanism of action of tetracyclines involves : \nSelect and explain. \nA. Binding of a component of the 50S ribosomal subunits, B. Inhibition of translocase activity, C. Blockade of binding of aminoacyl–tRNA to bacterial ribosomes, D. Selective inhibition of ribosomal peptidyl transferase', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]