Explanation:

- When demand for a product falls, it indicates that consumers are willing to buy less of the product at each price level.

- Option 1: Fall

- The equilibrium price generally decreases because the excess supply would put downward pressure on prices until a new equilibrium is reached.

- Option 2: Rise

- If demand falls, prices are unlikely to rise since producers need to sell their excess inventory, not raise prices.

- Option 3: Either of the two

- This is not typical in traditional demand-supply analyses. A clear trend usually occurs in one direction.

- Option 4: Neither of the two

- This would imply no effect, which isn't consistent with basic economic principles of demand and supply.