Which of the following is a common supply shifter?

Production costs are a fundamental factor that directly influences supply in a market. When production costs decrease, typically due to factors like cheaper raw materials or more efficient technologies, producers are more willing and able to supply more of a good or service at every price level. Conversely, if production costs increase, this can reduce the quantity supplied, as it may become less profitable for producers to manufacture or offer more of a product.

Understanding the relationship between production costs and supply helps explain fluctuations in market supply. For example, if a new technology is developed that lowers the cost of production, companies might increase their supply to take advantage of the higher profit margins, shifting the supply curve to the right. This effect illustrates the role of production costs as a primary shifter of supply in economic models.

The other factors mentioned—consumer expectations, marketing strategies, and product popularity—do not directly affect the supply side of the market in the same fundamental way that production costs do. While these can influence demand or the effectiveness with which products are marketed, they are not typically classified as direct supply shifters in microeconomic theory.