The bacterium Vibrio cholerae is harmless unless a lysogenic bacteriophage provides the gene coding for the cholera toxin, which converts the bacterium to the virulent form that causes cholera. Which of the following best explains how the gene encoding cholera toxin becomes part of the bacterial genome?
a. The bacteriophage inserts the toxin gene into the host cell DNA, and the gene is expressed with the rest of the host cell's genes.
b. The bacteriophage converts its toxin gene into mRNA, which is then translated by the host cell.
c. The bacteriophage makes copies of the toxin gene and expresses the copies inside the bacteriophage.
d. The bacteriophage transforms itself into a self-replicating protein that can survive inside the host cell.