The correct answer is C. fermentation.
Fermentation is a metabolic process that produces chemical changes in organic molecules, especially carbohydrates, without the involvement of oxygen. The process is used to make alcoholic beverages, such as beer and wine, and to produce bread and other baked goods.
Saponification is a chemical reaction that produces soap and glycerin from fats and oils. The reaction is catalyzed by an alkali, such as sodium hydroxide or potassium hydroxide.
Hydrogenation is a chemical reaction that adds hydrogen to an organic compound. The reaction is often used to convert unsaturated fats into saturated fats.
Hydrolysis is a chemical reaction that breaks down a compound into its constituent elements by the addition of water. The reaction is often used to break down proteins into amino acids.
In the reaction that converts sugar solution into alcohol, yeast cells convert the sugar into alcohol and carbon dioxide. The reaction is an example of fermentation.