Answer:
The correct answer is - prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.
Explanation:
The lac operon or the lactose operon is a operon that is essential for the many bacteria like Escherichia coli for metabolism and transport of the lactose.
In the presence of the lactose in the environment of the cell the lac genes are expressed due to the isomer of of lactose called allolactose binds to the Lac repressor protein and do not allow to bind it to lac operator. But in the absence of the lactose, the lactose utilizing enzymes are not expressed due to repressor bind to the lac operator and prevents the binding of RNA polymerase to the promoter.
