How can you show that σ (sigma factor) does not really accelerate the rate of transcription elongation?

“How will raising the temperature affect the transcription regulation of RodA? and what is the importance of performing this lab?

Using the transcription unit diagrammed below, in which exons are represented by blue boxes and introns are represented by the connecting lines.  You discover a single base deletion in region E of this DNA sequence. Regarding transcription, this mutation will likely: 1.) Result in an alteration to the mRNA sequence. 2.)Have no effect on transcription or the mRNA sequence 3.)Prevent transcription at the TATAA box 4.) Result in an increase or decrease in the amount of mRNA transcribed

What would be the effect on transcription of a short insertional mutation between the-10 box and the +1 site of transcription?