12. Line A below shows the peptide synthesized after transcription and translation of a piece of DNA. Line B shows the peptide synthesized after a mutation in this piece of DNA.
Line A: proline - arginine - aspartic acid - lysine - glycine
Line B: proline - glutamine - aspartic acid - lysine - glycine
The type of change in the DNA most likely to be responsible for the difference between the peptides is:
a. a frame-shift mutation
b. a base insertion
c. a base substitution
d. a base deletion
e. a silent mutation