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': 'After digestion by restriction endonucleases NA strands can be joined again by - \nSelect and explain. \nA. DNA polymerase, B. DNA ligase, C. DNA topoisomerase, D. DNA gyrase', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]