Which Statement About the Transcription Attenuation Mechanism Is TRUE

Which statement about the transcription attenuation mechanism is TRUE?

A) In some operons (e.g., the his operon) , attenuation may be the only regulatory mechanism.
B) Sequences of the trp operon leader RNA resemble an operator.
C) The leader peptide acts by a mechanism that is similar to that of a repressor protein.
D) The leader peptide gene of the trp operon includes no Trp codons.
E) The leader peptide is an enzyme that catalyzes transcription attenuation.