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': 'DNA supercoiling is done by : \nSelect and explain. \nA. DNA polymerase I, B. DNA polymerase II, C. DNA topoisomerase, D. DNA gyrase', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. DNA gyrase', 'role': 'assistant'}]