Base excision repair specifically targets damaged bases for removal and replacement with correct nucleotides.

• A. It repairs double-strand breaks via homologous recombination.
• B. It removes damaged bases and replaces with correct nucleotides.
• C. It synthesizes new DNA using RNA templates.
• D. It repairs mismatches during replication.

Answer: (B)

Base excision repair fixes small, specific base damages by removing the damaged base and filling in the correct nucleotide. The process starts when a DNA glycosylase recognizes and removes the damaged base, creating an abasic site. An AP endonuclease then nicks the backbone, and a DNA polymerase fills in the correct nucleotide before ligase seals the strand. This targeted removal and replacement of individual bases is precisely what base excision repair does, making the statement the best description.

This pathway is distinct from repairing double-strand breaks via homologous recombination, which handles large breaks; from mismatch repair, which corrects mispaired bases after replication; and from any mechanism that would synthesize DNA using RNA as a template.