In the absence of oxygen, yeast will use anaerobic fermentation instead of aerobic respiration to generate usable energy. Why?
A. Fermentation generates ethanol, which yeast need.
B. The Acetyl CoA produced by fermentation can then be used in the citric acid cycle.
C. Fermentation generates more ATP per glucose molecule than aerobic respiration.
D. In the absence of oxygen, fermentation reactions are necessary in yeast to regenerate NAD+.