Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?

A. The covalent bond in oxygen is unstable and easily broken by electrons from organic molecules.

B. The covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide.

C. The electrons have a higher potential energy when associated with water and carbon dioxide than they do in organic compounds.

D. Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O).