Final answer:
The demand curve for picture frames is influenced by the price of picture frames and related products. A decrease in the price of picture frames or a change in the price of printing photos would shift the demand curve. However, a celebrity promoting picture frames or an increase in income for most picture frame purchasers would not directly shift the demand curve.
Step-by-step explanation:
The demand curve for picture frames represents the relationship between the price of picture frames and the quantity demanded. In the given scenarios, option a. A decrease in the price of picture frames, and option b. A change in the price of printing photos, would both shift the demand curve for picture frames. This is because both scenarios affect the price and availability of related products, which can influence consumer demand for picture frames. On the other hand, option c. A celebrity promoting the wonders of picture frames, and option d. An increase in income for most picture frame purchasers, would not directly shift the demand curve for picture frames. While these factors may influence consumer preferences and purchasing power, they do not directly affect the price or availability of picture frames.
Learn more about Demand curve for picture frames