Since lactose is absent, the repressor protein is blocking the genes and stopping transcription.
Option A.
<h3><u>Explanation:</u></h3>
Lac operon or lactose operon is the genetic mechanism of the cell to produce the enzyme digesting lactose by production of lactase enzymes. The bacterial cell has this mechanism of lac operon which controls the production of definite amount of lactase only in presence of lactose, to minimize the wastage of proteins.
In the lac operon, there are cap sites, promoter region, operator region, and the genes producing enzymes. In presence of lactose, protein produced from the promoter attaches with the lactose which acts as inducer and frees up the operator sites for RNA polymerase to act. But in absence of glucose, the operator site remains blocked, as in figure B, restricting the lactase production.
