Correct Answer: Ethylene

Solution : The correct option is Ethylene.

Ethylene is a gas that is widely used to artificially ripen green fruit. Ethylene is a naturally occurring plant hormone that regulates fruit ripening. It is also utilised in the commercial ripening of fruits. The fruits themselves create ethylene gas. When exposed to ethylene gas, the fruits produce enzymes that break down the starches and other chemicals in the fruit, allowing it to ripen. Ethylene gas may be synthesised artificially by burning ethylene gas-producing substances like ethanol.