Which statement describes a shift of the supply curve rather than a movement along it?

• A. A movement along the supply curve caused by a price change.
• B. A shift of the supply curve caused by a non-price factor such as input costs.
• C. A change in the quantity supplied due to a change in price.
• D. A movement along the supply curve as price changes.

Answer: (B)

Supply curves show how much producers are willing to sell at each price. A movement along the curve happens when the price changes, so the quantity supplied changes but the curve itself stays in the same position. A shift of the curve happens when something other than price changes, altering the overall willingness or ability to produce across all prices. Non-price factors like input costs can make production less profitable at every price, shifting the supply curve to the left; improvements in technology or changes in input prices can shift it to the right. So the statement describing a shift is the one that points to a non-price factor affecting supply across all prices.