Answer:
The correct answer would be - option D. perform anaerobic respiration in the absence of oxygen.
Explanation:
Yeast is a facultative anaerobic single-cell organism that can live without oxygen. If yeast cells did not get the oxygen they use anaerobic respiration to get the energy.
If the baker activates these cells and stops them to get oxygen the yeast cells have to switch to anaerobic respiration to survive and produces ethanol and releases carbon dioxide.