Which of the following mutations of the trpL region would be least likely to affect attenuation of trp operon transcription?
a) a deletion of region 4
b) a deletion of the uracil nucleotides immediately following region 4
c) a deletion of the start (AUG) codon of the trpL polypeptide
d) an insertion of two nucleotides immediately after the polypeptide stop codon
e) an insertion of two nucleotides immediately following the polypeptide start codon