Which of the Following Is Least Likely to Be Observed $\beta$

Which of the following is least likely to be observed in a nonmutant bacterial cell?

A) Presence of $\beta$ -galactoside transacetylase at a high concentration when $\beta$ -galactoside is present at a low concentration
B) Production of $\beta$ -galactoside transacetylase at very low levels in the absence of lactose
C) Production of $\beta$ -galactoside transacetylase at very low levels when glucose is abundant
D) Production of $\beta$ -galactoside transacetylase at high levels when lactose is at a high concentration and glucose is not available
E) Presence of both $\beta$ -galactoside transacetylase and $\beta$ -galactoside in very low concentrations