Why is glycerol considered a non-fermentable sugar, and what is its role in aerobic conditions?

Glycerol is non-fermentable because it produces excess NADH, which cannot be efficiently used in fermentation; it is used in aerobic conditions for energy production.

Glycerol is non-fermentable because it lacks the necessary enzymes for glycolysis; it is used in aerobic conditions to synthesize fatty acids.

Glycerol is non-fermentable because it cannot be phosphorylated; it is used in aerobic conditions to produce glucose.

Glycerol is non-fermentable because it is toxic to cells; it is used in aerobic conditions to detoxify the cell.