In general, a large-scale mutation affects "<span>D. one or a few nucleotides in the DNA" which can either be completely random or through certain forces that occur in life. </span>
<u>The inducer in the lac operon is allolactose. Allolactose is the inducer of lac operon since it turns on, or induces the expression of the lac genes. </u>
In the presence of lactose in the medium, some amount of lactose will be converted to allolactose by the enzymes β-galactosidase present in the cell.
Consequently Allolactose binds to the repressor molecule, hence reducing the repressor's affinity for the operator site.
