What causes a demand curve to shift rather than move along it?

• A. A change in the price of the good.
• B. A change in the quantity demanded due to a price change.
• C. A change in non-price determinants such as income, tastes, or prices of related goods.
• D. A change in the supply curve.

Answer: (C)

Non-price determinants change the overall willingness or ability to buy at every price, so the entire demand curve shifts. When factors like income, consumer tastes, or the prices of related goods change, people adjust how much they want to buy across all price levels, pushing the curve left (less demand) or right (more demand).

In contrast, a change in the price of the good itself causes movement along the same curve, not a shift of the curve, because it just changes how much is bought at that particular price. A change in the quantity demanded due to a price change is that movement along. A change in the supply curve shifts supply, not demand.