Answer:
(B) adding the free nucleotides to the complementary strand of DNA
Step-by-step explanation:
A DNA polymerase is an enzyme capable of creating new DNA molecules by sequentially adding nucleotides to the three prime (3')-end of a DNA strand. A DNA strand is a polynucleotide chain composed of a linear series of nucleotides, each consisting of a deoxyribose sugar, and phosphate, and a base (i.e., thymine, guanine, cytosine and adenine). Before a cell starts to divide, it needs first to replicate its genetic material by using DNA polymerases that duplicate the cell's DNA during the interphase (S phase). During this process (DNA replication), an enzyme known as helicase unwinds the DNA molecule, which is made up of two antiparallel strands oriented in opposite 3′-5′ directions to each other. Subsequently, each strand is used as a template for its replication through DNA polymerases that can add nucleotides (one at time) to an existing short fragment of RNA, i.e., the primer sequence, which is paired with the template DNA strand.