Why Would Bacteria Evolve So That the Presence of Tryptophan

Why would bacteria evolve so that the presence of tryptophan inhibits its own production?

A) Producing the enzymes that synthesize tryptophan is metabolically expensive,so it is wasteful to make them when tryptophan levels are high and its synthesis is not necessary.
B) Producing high levels of tryptophan inhibits the production of other amino acids,so inhibiting its production allows all amino acids to be synthesized at equal concentrations.
C) High levels of tryptophan causes cells to become unresponsive to external stimuli,so its production must be regulated.
D) High levels of tryptophan inhibit cellular respiration and the synthesis of ATP,so its production must be regulateD.
E) All of these choices are TRUE.