The biodegradable substance is decomposed by biological processes like decomposition by microorganisms.
The cloth bag is a biodegradable material since the cloth is usually made of natural fibers like jute or cotton. Hence, the correct answer is option (i) cloth bag.
Explanation of the incorrect option:
The plastic bag is made up of plastic which is a non-biodegradable substance. Non-biodegradable substances are not decomposed by the decomposers like bacteria or fungi. Hence, this is an incorrect option.
This will stay in the environment for a very long time and become a pollutant without recycling or reuse.