A decrease in supply is depicted by a:

• A. leftward shift of the supply curve
• B. rightward shift of the supply curve
• C. movement down along the supply curve
• D. movement up along the supply curve

Answer: (A)

Verified step by step guidance

1. Understand that the supply curve shows the relationship between the price of a good and the quantity supplied, holding other factors constant.
2. Recall that a change in supply means the entire supply curve shifts, while a change in quantity supplied means movement along the same supply curve.
3. Recognize that a decrease in supply means producers are willing to supply less of the good at every price, which shifts the supply curve to the left.
4. Contrast this with an increase in supply, which would shift the supply curve to the right, indicating more quantity supplied at every price.
5. Note that movements up or down along the supply curve represent changes in quantity supplied due to price changes, not shifts in supply.