What does a decrease in income imply for the demand curve?

A decrease in income typically leads to a leftward shift in the demand curve for normal goods. This shift reflects a decrease in consumers' purchasing power; as people have less income, they are likely to buy less of various products, which reflects a reduced quantity demanded at each price level.

For normal goods, which are goods that consumers buy more of when their income increases, a decrease in income results in consumers scaling back their purchasing decisions. This action manifests on a graph as the entire demand curve moving to the left. This indicates that at every price point, consumers will demand fewer goods than before because they can no longer afford to purchase as much due to the drop in their income.

In contrast, other options do not accurately depict the relationship between income changes and demand curve movements. A rightward shift would suggest an increase in demand, becoming vertical indicates perfectly inelastic demand (which does not relate to income effects), and remaining unchanged would imply that income has no effect on demand, all of which do not align with the economic principle governing demand in relation to income changes.