What is the substrate in the following story?

In your body, DNA Polymerase is a protein that functions to speed up the process of building DNA. DNA Polymerase has the correct shape to recognize small chemicals called nucleotides. After attaching to nucleotides, DNA polymerase then quickly bonds the nucleotides together to form a long DNA molecule.

Group of answer choices

Nucleotide

DNA Polymerase

Catalase

Protein

DNA