What state is the repressor protein in when tryptophan is absent?

A:the repressor protein is inactive

B: the repressor protein is active

C: the repressor protein is not expressed

The correct answer here is B - in the case where tryptophan is absent, it is likely that the repressor protein is active. In cases such as this, we know that the synthesis of certain things such as mRNA will be prevented due to the fact that tryptophan is present.