Consider the market for gasoline. Buyers will move along the demand curve when:

• A. the price of substitute goods changes
• B. the price of gasoline changes, holding all other factors constant
• C. the income of buyers increases
• D. the preferences of buyers change

Answer: (B)

Verified step by step guidance

1. Understand the difference between a movement along the demand curve and a shift of the demand curve. A movement along the demand curve occurs when the price of the good itself changes, holding all other factors constant.
2. Recognize that changes in the price of substitute goods, income of buyers, or preferences of buyers cause the entire demand curve to shift, not just a movement along it.
3. Identify that when the price of gasoline changes, buyers respond by moving to a different quantity demanded along the same demand curve, which is called a movement along the demand curve.
4. Recall that a movement along the demand curve is represented by a change in quantity demanded due to a change in the good's own price, while shifts in demand are caused by changes in external factors like income or preferences.
5. Conclude that the correct condition for buyers moving along the demand curve is when the price of gasoline changes, holding all other factors constant.