To conserve energy the genes and e coli arealways active never active only active when needed or nonfunctional

To conserve energy, the genes in E coli are ONLY ACTIVE WHEN NEEDED.
Gene regulation refers to the turning on and off of genes. Gene regulation makes it possible for cells to produce specific proteins only when they are needed.  In E coli for instance, the necessary enzyme for the metabolism of lactose is only turned on only when lactose is present, this is done as mean of preserving energy.

The answer to your question is C