Ceteris Paribus in Demand Curves

Steps:

• A demand curve graphs quantity demanded versus price of the good, holding other factors constant.
• Factors like income, expectations, and interest rates shift the curve if they change.
• Price of the good itself varies along the curve to show different quantities demanded.
• Thus, only price changes when drawing the curve; others remain fixed.

Why C is correct:

• The law of demand defines the curve as quantity demanded at varying prices, so house price is not held constant.

Why the others are wrong:

• A shifts demand if incomes change, so assumed constant for the curve.
• B shifts demand if expectations change, so assumed constant for the curve.
• D affects affordability and shifts demand, so assumed constant for the curve.

Final answer: C