In microeconomics, when we move along a given demand curve for a good, what is changing?

• A. The entire demand curve shifts because consumer income changes (a change in demand).
• B. The entire demand curve shifts because tastes and preferences change (a change in demand).
• C. The supply curve shifts because input prices change.
• D. The quantity demanded changes in response to a change in the good’s own price (a change in quantity demanded).

Answer: (D)

Verified step by step guidance

1. Understand the difference between a 'change in demand' and a 'change in quantity demanded'. A change in demand means the entire demand curve shifts due to factors like income or tastes, while a change in quantity demanded means movement along the same demand curve due to price changes.
2. Identify that moving along a given demand curve implies the demand curve itself does not shift; instead, the quantity demanded varies as the price of the good changes.
3. Recall that factors such as consumer income or preferences cause the demand curve to shift, representing a change in demand, not movement along the curve.
4. Recognize that a change in the supply curve is unrelated to movements along the demand curve and is caused by factors like input prices.
5. Conclude that when moving along a given demand curve, the variable changing is the quantity demanded in response to the good's own price, which is called a change in quantity demanded.