Answer: a) citrate
Step-by-step explanation:
Aerobic respiration involves glycolysis and the tricarboxylic acid cycle (Krebs cycle). Pyruvate is completely degraded to carbon dioxide (CO2) and in the process, NAD is converted to NADH + H + The enzymes citrate synthase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase are the regulators of metabolic flow through the Krebs cycle and are subject to allosteric control involving NADH as inhibitor and Ca + and ADP as activators.