Which of the following changes is least likely to produce a phenotypic change in an organism and why?

A. UAG to UAC because a change in the last amino acid of a codon, produces very little change.

B. UGA to UAA because both code for a stop codon therefore there is no effect on the protein produced.

C. AUG to AUA because as long as the first to amino acids are the same, there is little effect on the protein produced.

D. GAU to GGU because a change in the second amino acid of a codon does not have much effect on the protein produced