Concept:A change in price causes a movement along the supply curve, not a shift of the whole supply curve.Explanation:The graph shows one upward-sloping supply curve. This curve shows a direct relationship between price and quantity supplied. When the price rises from P1 to P2, the quantity the seller is willing to supply also increases. This is seen as a movement upward along the same supply curve. It is not an increase in supply, because the supply curve itself has not shifted. If supply had increased, the whole curve would shift to the right. Since the change is caused by a rise in the price level, the graph shows an increase in quantity, which means an increase in the quantity supplied.Answer:D. an increase in quantity.
