Sigma (σ)Factors Can Regulate the Initiation of Transcription

Multiple Choice

Sigma (σ) factors can regulate the initiation of transcription.Which of the following is not an example of σ regulation?

A) Some σ factors recognize promoters for genes whose products are necessary when the organism is under stress, such as heat shock.
B) Some σ factors recognize genes necessary for nitrogen utilization.
C) Bacteriophages may code for specific σ factors that bind the core RNA polymerase and result in recognition of viral promoters.
D) There are many σ sigma factors associated with eukaryotic organisms.