The correct option is C The assertion is true but the reason is false
Fermentation is an enzyme catalysed process, where organisms convert sugar to alcohol or an acid anaerobically. It is widely used in the production of yogurt, bread, and alcoholic beverages like beer, wine, whisky, etc.
Saccharomyces cerevisiae, is used to convert the sugars present in malted cereals, fruit juices, etc. into alcohol and carbon dioxide under anaerobic conditions. This process is called alcoholic or ethanol fermentation. Carbon dioxide, and not oxygen, is the by product in this reaction.