Ans. (c) unwinding the helix.
DNA polymerase is a DNA replicating enzyme, which synthesizes new DNA molecules from the template DNA molecules. DNA polymerase adds new nucleotide on the growing DNA strand, checks for errors occurred during replication, and repairs those errors.
It does not have helicase activity, means it cannot unwind the double-stranded DNA helix.
Thus, the correct answer is option (c).