When Is a Single Base Substitution Mutation Least Likely to Be

Multiple Choice

When is a single base substitution mutation least likely to be deleterious?

A) when the base change results in an amino acid substitution at the active site of an enzyme
B) when the base change results in an amino acid substitution that alters the tertiary structure of the protein
C) when the single base change results in a stop codon
D) when the single base change results in a codon that specifies the same amino acid as the original codon