Answer:
a. an increase in output and an increase in the price level.
Step-by-step explanation:
If Aggregate Demand increases, this will result in an increase in output and an increase in the price because short run aggregate demand measures total output for a single nominal price level
In the long-run, increases in aggregate demand cause the price of a good or service to increase. When the demand increases the aggregate demand curve shifts to the right.
Also, increased demand for a product in the long run will lead to increased output being supplied.
The aggregate supply determines the extent to which the aggregate demand increases the output and prices of a good or service.