After DNA fragments with matching sticky ends are temporarily joined by complementary base pairing, the union can be made permanent by the "pasting" enzymea. DNA helicase. b. DNA ligase. c. ATP methylase. d. DNA polymerase.

The correct option is b. DNA ligase

Explanation:

DNA ligase is an enzyme that joins DNA fragments. If two DNA fragments or molecules have complementary ends, the ligase can join them together to form a single and intact DNA molecule, without interruptions. This is because the ligase enzyme seals the space between the molecules to form a single DNA fragment.

The others enzymes have different functions:

DNA helicase is characterized by separating DNA from double strands into single strands and acts in DNA replication.

ATP methylase plays an important role in DNA replication when determining the beginning of replication that has already been replicated or not.

DNA polymerase is an enzyme that is responsible for catalyzing the polymerization of the new strand of DNA during the replication of this molecule.