As the price of tablet computers has fallen, more shoppers buy tablets instead of laptops, since the two serve as substitutes. What does the falling price of tablets do to the demand curve for laptops?

1. Tablets and laptops are substitutes, so the price of one affects demand for the other. 2. A lower tablet price is a change in a related good's price, which shifts the laptop demand curve rather than moving along it. 3. Fewer buyers want laptops at every price once tablets become cheaper, so the laptop demand curve shifts left. 4. Options B and D describe the wrong mechanism: B ignores that this is a shift, and D misidentifies which curve moves. _Source: OpenStax Principles of Macroeconomics for AP Courses (CC BY 4.0), Ch 3 "Demand and Supply", section 3.2 | Shifts in Demand and Supply for Goods and Services_