Which of these events could be a result of an error made during transcription?

The right answer is A codon sequence is incorrect.

Explanation:

Biologists have compared the corresponding DNA and RNA sequences in B cells (white blood cells), the material being provided by various ongoing sequencing projects. They identified more than 10,000 sites where the two molecules differ, with about 40 percent of the genes having at least one transcription error. This error can be found at the level of the codons of the amino acids, which implies a change of one amino acid by another.