Answer:
D. Lactic acid
Step-by-step explanation:
Fermentation takes place When a molecule of glucose is broken down into pyruvate molecules. Fermentation is another source of gaining energy from cellular respiration.
During fermentation, electrons from electron transport chain combine with pyruvate molecules, and this reaction further proceeds in the presence of endogenous organic electron receptors. These organic electron receptors form waste products.
Common products synthesized during fermentation are lactic acid, lactose, and hydrogen. Lactic acid is formed when NADH transfers an electron to pyruvate molecule.