What are the two main steps involved in alcohol fermentation?

Decarboxylation of pyruvate to acetaldehyde, followed by reduction of acetaldehyde to ethanol.

Decarboxylation of glucose to acetyl-CoA, followed by reduction to ethanol.

Oxidation of glucose to pyruvate, followed by reduction of pyruvate to lactate.

Oxidation of ethanol to acetaldehyde, followed by reduction to pyruvate.