The correct option is C.
Fermentation is the metabolic process which involves the break down of sugar in the absence of oxygen to produced gases, organic acids or alcohols. Fermentation can only occur in the absence of oxygen. Fermentation generates much less ATP than cellular respiration. There are two types of fermentation, alcoholic and lactic acid fermentation; lactic fermentation does not produce carbon dioxide. During the process of fermentation, NAD+ is always generated from NADH by the transfer of electron to pyruvate or a derivative, thus, fermentation makes NAD+ to keep glycolysis going.
