Part a the presence of a mutant lac repressor that could not bind lactose would result in transcription even when lactose was present because the mutant repressor would remain bound to the lac see section 18.3 (page 373) . view available hint(s) the presence of a mutant lac repressor that could not bind lactose would result in transcription even when lactose was present because the mutant repressor would remain bound to the lac see section 18.3 (page 373) . no; operator lots of; operator lots of; promoter no; promoter

The presence of a mutant lac repressor that could not bind lactose would result in no transcription even when lactose was present because the mutant repressor would remain bound to the lac operator 

The transcription of lac operator is controlled by the lac repressor. When lactose is present, the lac repressor normally will bind to the lactose, removing itself from the lac operator so it could be transcripted. 
In this case, the mutation makes the lac repressor keep binding to the lac operator so the result would be no transcription even when lactose present.

Your answer is b. codominant