Concept:A shift of the entire demand curve represents a change in demand caused by non-price factors.Explanation:A movement along the same demand curve shows a change in quantity demanded due to price.A shift of the whole demand curve leftward or rightward occurs when factors like income, tastes, population, or prices of related goods change.These factors alter consumer desire to buy a good at every price, not just at one price.Therefore, a curve shift directly indicates a change in demand.Answer:B. change in demand