Answer: a movement along the demand curve.
Step-by-step explanation:
When the price of a good changes, demand is supposed to react to that by moving along the demand curve because the demand curve is a visual representation of the goods demanded by people at various prices.
For instance, if the price of a normal good increases, the demand will likely decrease and there will be a movement up the demand curve to show that less goods are being demanded. The reverse holds true.