The correct options are
B In the absence of lactose the repressor binds with the operator region
C The z-gene codes for permease
In the lac operon, lactose binds with the repressor to inactivate it and leads to the transcription of the genes in the operon. The lac operon consists of three structural genes, and a promoter, a terminator, regulator, and an operator. The three structural genes are: lacZ coding for β - galactosidase, lacY β - galactosidase permease, and lacA β - galactosidase transacetylase.