Which of the following can cause a shift in the demand curve?

A shift in the demand curve indicates a change in the quantity demanded at every price level, which can occur due to several factors that influence consumer buying behavior. Changes in consumer preferences are a key driver of demand curve shifts. When preferences evolve—perhaps due to trends, advertising, or a change in tastes—consumers may desire more of a good at any given price, leading to an outward shift in the demand curve. For instance, if a new health report touts the benefits of a certain food item, consumers may increase their demand for it, propelling the demand curve to the right.

In contrast, while changes in weather patterns can impact the demand for specific goods (like ice cream in summer or hot beverages in winter), they usually create movements along the demand curve rather than a substantive shift in overall demand. Changes in production costs and technology primarily affect supply, not demand. They can modify the supply curve, impacting the equilibrium price and quantity but do not directly cause shifts in demand itself. Thus, the influence of consumer preferences makes it the correct answer regarding what can shift the demand curve.