An inferior commodity is one which is consumed in smaller quantities when the income of consumer

Becomes nil
Remains the same
Falls
Rises

The correct answer is C. Falls.

An inferior good is a good whose demand decreases when consumer income increases. This is because as consumers have more money, they tend to switch to goods that are considered to be of higher quality or status. Inferior goods are often necessities, such as food and clothing, that consumers are willing to spend less money on when they have more money to spend.

Option A is incorrect because if a consumer’s income becomes nil, they will not be able to consume any goods, inferior or otherwise.

Option B is incorrect because if a consumer’s income remains the same, their demand for inferior goods will also remain the same.

Option D is incorrect because if a consumer’s income rises, their demand for inferior goods will decrease.