In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of in the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of atp, pyruvate, and acetyl coa atp, co2, and lactate atp, co2, and ethanol (ethyl alcohol) atp, nadh, and pyruvate

Anaerobically (in absence of oxygen), yeast cells may obtain energy by fermentation, resulting in the production of ATP, CO2 AND ETHANOL.  This is called ethanol fermentation or alcoholic fermentation where sugars such as glucose, fructose, and sucrose is converted into cellular energy (ATP), producing ethanol and carbon dioxide as by products.

Bis the correct answer.