Demand Curve Shifts vs. Movements

Steps:

• Recall demand curve shows quantity demanded at various prices, holding other factors constant.
• Identify non-price factors (e.g., income, related goods prices) cause shifts; own price causes movement along curve.
• Evaluate options: A, B, D affect non-price determinants; C is own price change.
• Confirm C leads to quantity change on existing curve, not new curve.

Why C is correct:

• Per the law of demand, a change in the good's price causes movement along the curve (inverse price-quantity relationship), not a shift.

Why the others are wrong:

• A: Complement price change alters demand for the good (e.g., cheaper complement increases demand, shifting curve right).
• B: Substitute price change affects demand (e.g., cheaper substitute decreases demand, shifting curve left).
• D: Income change shifts demand curve (right for normal goods, left for inferior goods).

Final answer: C