
Given above is the functioning of the normal lac operon in E. coli.
The question says that due to mutation, the product of i gene which is the repressor, cannot bind to the inducer molecule which is lactose.
The repressor gene binds to the operator region and does not allow the binding of RNA polymerase to the promoter region in the mRNA molecule.
If the repressor is absent, then it will not bind to the operator, the binding of RNA polymerase to the promoter region will be open always and there will be the transcription of lac z, y, and a genes.