Which action best describes the general outcome of mismatch repair after replication?

• A. Replaces damaged bases with random nucleotides
• B. Repairs thymine dimers by photoreactivation
• C. Corrects mismatches by removing the error-containing segment of the newly synthesized strand and resynthesizing
• D. Inhibits replication fork progression

Answer: (C)

Mismatch repair after replication fixes errors by removing a short stretch of the newly synthesized strand that contains the mispaired bases and then resynthesizing that segment using the original template strand as a guide, followed by sealing the nick. This strand-specific excision and resynthesis restore the correct sequence and greatly improve fidelity, ensuring the error is not propagated. The other options describe different repair or damage responses: thymine dimers can be repaired by photoreactivation or other damage-specific pathways, not by mismatch repair; replacing bases randomly would not preserve the correct sequence; and inhibiting the replication fork would disrupt replication rather than fix a mispair.