Answer:
Option D, Essentially none
Explanation:
The essential condition for lac operon to express its subsequent proteins i.e laz A, lacZ and lacY are as follows –
a) Absence of glucose
b) Presence of Lactose.
In fact absence of glucose is must. In case when lactose is absent and glucose is present then the lac z sub-protein whose product is β-galactosidase is not expressed. In fact in lac z breaks down lactose into glucose and galactose in absence of glucose.
Hence, option D is correct