If long-run aggregate supply (lras) shifts right, we know for certain that there has been an increase in ad. Option b
This a curve that depicts the correlation between price level and real GDP that would exist if all prices, including nominal wages, were completely flexible; prices can vary along the LRAS, but production cannot because it represents the output at full employment.
As productivity rises or the cost of essential inputs decreases, the aggregate supply curve shifts to the right, allowing for a combination of lower inflation, more production, and lower unemployment.
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