DNA polymerase III is a processive enzyme, which means that

a. it does not dissociate from the growing strand after it has attached a nucleotide to the 3′ end.
b. it makes a new strand very quickly.
c. it proceeds toward the opening of the replication fork.
d. it copies DNA with relatively few errors.

The correct answer is option a. "it does not dissociate from the growing strand after it has attached a nucleotide to the 3′ end".

Explanation:

In molecular biology, processivity is defined as the ability of an enzyme to catalyze consecutive reactions without releasing its substrate. For DNA polymerase III it means that it will continue DNA synthesis without dissociating from the DNA template once it is attached to the 3′ end. This ability is practical for DNA synthesis, since it usually involves the growing of large strands of DNA.