In human aerobic metabolism, which molecule is the primary waste product ultimately produced from complete oxidation of carbon fuels in the citric acid cycle and oxidative phosphorylation?

• A. $C_6{H}_{12}{O}_6$ (glucose)
• B. $C_2{H}_3{O}_2$− (acetate)
• C. $C_3{H}_4{O}_3$− (pyruvate)
• D. $C_1{O}_2$ (carbon dioxide)

Answer: (D)