Correct Answer - C
Nucleases are the enzymes that remove nucleotides or produce nick in the DNA strand. Exonuclease remove nucleotides from the free ends of DNA while endonucleas produce internal nicks in DNA. Now, the desired gene is inserted and then the cut ends are sealed with the help of DNA ligases. Ligases are also called molecular glue as they join together two DNA strand by forming phosphodiester bond between adjacent nucleotides.
