In Gene Regulation and Control,repression Is Defined as The

In gene regulation and control,repression is defined as the:

A) internal change in the original nucleotide sequence of a gene or genes within an organism's genome.
B) mechanism of genetic control in which genes are induced only when the substrate to be degraded by enzymatic action is present.
C) change of the bacterial genotypes through the exchange of DNA from one cell to another.
D) mechanism of genetic control in which genes are not transcribed and therefore are not expressed in the presence of those target products in sufficient supply.