19. Under anaerobic conditions, yeast produce ethanol by fermentation of pyruvate at the end of glycolysis. Why? (2.5 points)(A)Pyruvate to ethanol fermentation reduces toxic CO2 levels.(B)Glycolysis substrate-level phosphorylation changes pyruvate to ethanol.(C)Ethanol produced from pyruvate regenerates NAD+, which is necessary for starting new rounds of glycolysis.(D)To add electrons (and protons) to ethanol for making lactate.