Pyruvate dehydrogenase complex connects glycolysis to respiration. Which is a correct mechanism for how the activity of this enzyme complex is regulated?

A) There is no need to regulate this enzyme complex.
B) The activity is inhibited by CoA and NAD+.
C) Gene expression is repressed by carbon starvation and low oxygen levels.
D) The activity is inhibited by citrate.
E) The activity is enhanced by the presence of acetyl-CoA and NADH.