Which of the following would cause a shift to the right of the market demand curve for a normal good?

• A. An increase in population
• B. A decrease in population
• C. An increase in the price of a substitute
• D. An increase in supply

Answer: (A)

A shift in the demand curve happens when a non-price factor changes how much buyers want to purchase at every price. For a normal good, increasing the number of buyers in the market directly raises total demand. When population grows, there are more people who could buy the good, so at each price consumers collectively want to buy more, and the entire demand curve shifts to the right.

Decreasing population would do the opposite and shift demand to the left. An increase in supply affects the supply side, not the demand curve. An increase in the price of a substitute would also raise demand for this good, shifting the curve right, but the scenario given here centers on a larger market of buyers, which is the clearest driver of the rightward shift.