A GraphThis is a graphical representation showing 4 different lines line A perpendicular to Y axis line B upward sloping and line C parallel to X axis and line D downward sloping Represented by a combination of real output and price level on X and Y axis respectively. Refer to the above diagram. If the price level rises above P1 because of an increase in aggregate demand, the: Multiple Choice economy's output first will decline, then increase, and finally return to Q1. long-run aggregate supply curve C will shift upward. short-run aggregate supply curve B will automatically shift to the right. economy will move up along curve B and output will temporarily increase