RNA Polymerase in a Prokaryote Is Composed of Several Subunits

Multiple Choice

RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism in having such variability in RNA polymerase?

A) It might allow the translation process to vary from one cell to another.
B) It might allow the polymerase to recognize different promoters under certain environmental conditions.
C) It might allow the polymerase to react differently to each stop codon.
D) It might alter the rate of translation and of exon splicing.