Which of the following mutations is most likely to cause a phenotypic change?
a) a duplication of all or most introns
b) a large inversion whose ends are each in intergenic regions
c) a nucleotide substitution in an exon coding for a transmembrane domain
d) a single nucleotide deletion in an exon coding for an active site
e) a frameshift mutation one codon away from the 3' end of the nontemplate strand