Which gas is released during the fermentation of the sugar of grapes…

The correct answer is Option (2) → Carbon dioxide (CO₂)

NCERT (2026-27 edition):
7.5 Some Commercially Important Alcohols – “In wine making, grapes are the source of sugars and yeast. As grapes ripen, the quantity of sugar increases and yeast grows on the outer skin. When grapes are crushed, sugar and the enzyme come in contact and fermentation starts. Fermentation takes place in anaerobic conditions i.e. in absence of air. Carbon dioxide is released during fermentation.”