In an experiment you add increasing amount of sigma factor to a mixture of DNA fragment and core polymerase in vitro. You also add [14C]ATP and [γ-32P]ATP in the mixture and check the rate of incorporation. Results show that the incorporation of both of this labels increase on adding more sigma factor. What will you conclude from your observation?$

• A. Sigma confers specificity and increases transcription rate
• B. Sigma increases initiation and elongation rate
• C. Sigma increases initiation of transcription rate
• D. Sigma causes faster elongation