In the context of DNA replication, what is the primary function of DNA ligase?

• A. It adds nucleotides to the growing DNA strand in the 5' to 3' direction using a DNA template.
• B. It synthesizes short RNA primers to provide a free 3' end for DNA polymerase to extend.
• C. It seals nicks in the sugar-phosphate backbone by forming phosphodiester bonds, joining Okazaki fragments into a continuous DNA strand.
• D. It unwinds the DNA double helix ahead of the replication fork by breaking hydrogen bonds between base pairs.

Answer: (C)