Which of the following is NOT a reason for a shift in the supply curve?

The correct answer identifies that a shift in the supply curve is not caused by changes in consumer preferences. The supply curve represents the relationship between the price of a good or service and the quantity that producers are willing to supply, while consumer preferences are related to demand.

When there is a change in production costs—such as the cost of raw materials or labor—this influences how much producers are willing to supply at various price levels, leading to a leftward or rightward shift in the supply curve. Similarly, advances in technology can increase efficiency in production, allowing suppliers to increase output, which shifts the supply curve to the right. Additionally, changes in the number of suppliers in the market can also affect the overall supply available; an increase in suppliers typically leads to a rightward shift in the supply curve due to greater market competition.

In contrast, a change in consumer preferences affects demand rather than supply. If consumers start favoring a different product, the demand curve shifts, impacting the equilibrium price and quantity but not the supply curve itself.