Sigma (A)factors Can Regulate the Initiation of Transcription

Multiple Choice

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

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