Answer:
The correct answer would be DNA ligase.
DNA ligase is the enzyme which catalyzes the formation of phosphodiester in DNA molecule.
It is used in replication as well as repair of the DNA.
During replication, it helps in joining the newly formed Okazaki fragments by catalyzing the formation of phosphodiester bond between the sugar-phosphate backbones of the fragments.
In DNA repair, it helps in sealing the nicks formed during the repair system such as nicks formed during nucleotide excision repair.
In molecular biology, DNA ligases are now used to produce recombinant DNA.