as it’s the only option that shows the addition of nucleotides into a segment of DNA
The other three choices (ARSTUVOXYZ, BRSTUVOXYZ, and CRSTUVOXYZ) do not show an insertion mutation. ARSTUVOXYZ is missing a nucleotide compared to the original sequence (R), so it would be a deletion mutation. BRSTUVOXYZ has a substitution mutation (B instead of R). CRSTUVOXYZ also has a substitution mutation (C instead of R).
