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: Biochemistry
[{'content': 'The sigma (cr) subunit of prokaryotic RNA polymerase: \nSelect and explain. \nA. Binds the antibiotic rifampicin, B. Is inhibited by a-amanitin, C. Specifically recognizes the promoter site, D. Is pa of the core enzyme', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Specifically recognizes the promoter site', 'role': 'assistant'}]