Which of the following is the primary difference in regulation between the lactose and tryptophan operons:

W) tryptophan activates its repressor and lactose leads to an inactive repressor

X) when tryptophan is present, the repressor is inactive and the opposite is true for allolactose in the lac operon

Y) allolactose is considered a co-repressor whereas tryptophan is actually an inducer

Z) when tryptophan is not present, the co-repressor is able to inactivate the promoter directly
W) TRYPTOPHAN ACTIVATES ITS REPRESSO AND LACTOSE LEADS TO AN INACTIVE REPRESSO