In an enzymatic reaction involving NADH or NADPH, reduction of a substrate accompanies the oxidation of these carrier molecules to NAD⁺ or NADP⁺, respectively. What else typically happens in such a reaction?

A) A molecule of water is released to the solution upon completion of the reaction.
B) A proton is released during the oxidation of the carriers.
C) A proton is taken up by the substrate that is being reduced.
D) A proton is taken up by the carrier molecule that is being oxidized.
E) A phosphate group is transferred to the substrate.