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 is A: the repressor protein is inactive

Without tryptophan, the repressor protein recedes into inactivity.

If tryptophan is absent then tryptophan repressor protein is in an inactive state When the amino acid tryptophan becomes plentiful in the cell, it binds to and activates the tryptophan repressor, which blocks the synthesis of additional tryptohan. So answer is B