Which one of the following statements about the trp operon is true?
A.
the Trp repressor is a product of the trp operon.
B.
the Trp repressor, like the Lac repressor, is a tetramer of identical subunits.
C.
the Trp repressor binds to tryptophan.
D.
tryptophan activates expression from the trp operon.