Concept:An inferior good is defined as a good whose quantity demanded falls when the consumer's income rises.
Explanation:Income and demand usually move together for normal goods, luxuries, and necessities, but not for inferior goods.
For a normal good, a rise in income leads to an increase in purchases.
For a luxury, purchases increase more than proportionally as income rises.
For a necessity, purchases remain roughly the same or increase only slightly with income.
An inferior good, however, has a negative relationship with income: as income increases, consumers can afford better alternatives, so they buy less of the inferior good.
For example, if a person's salary increases, they may buy less cheap tea and instead buy premium coffee or branded goods.
Therefore, the good described in the question is an inferior good.
Answer:Option D: an inferior good