What enzyme removes RNA primers in eukaryotic replication?

• A. DNA polymerase fills in the gaps after RNA primer removal.
• B. DNA ligase seals nicks after primer removal.
• C. RNase H (and related nucleases) to remove RNA primers; DNA polymerase fills in with DNA.
• D. Helicase removes RNA primers.

Answer: (C)

RNA primers in eukaryotic replication are removed by RNase H and related nucleases, which digest the RNA within RNA-DNA hybrids. After this removal, DNA polymerase delta fills in the resulting gaps with DNA, and DNA ligase seals the remaining nicks to complete the lagging or leading strand synthesis. The other options don’t fit because removing the RNA primer is not the job of DNA polymerase or helicase, and ligase only seals nicks after the primer is gone.