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': 'Inhibitors of DNA synthesis - \nSelect and explain. \nA. Penicillin, B. Polymyxin, C. Chloramphenicol, D. Actinomycin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Actinomycin', 'role': 'assistant'}]