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
After digestion by restriction endonucleases NA strands can be joined again by - 
Select and explain. 
A. DNA polymerase, B. DNA ligase, C. DNA topoisomerase, D. DNA gyrase
B: DNA ligase
Answer: B: DNA ligase 
Explanation: None