If a mutation occurs in the gene for the lac repressor and results in a repressor that does not bind lactose, which of the following will be observed?
a. the mutant will not be able to grown on lactose.
b. the mutant will only be able to grow on lactose.
c. the mutant will be able to grow on lactose and on other sugars.
d. the mutant will be harmed by the presence of lactose.