When the price level changes, this: decreases the level of aggregate supply in the long run. increases the level of aggregate supply in the long run. decreases the level of aggregate supply in the long run only at very high levels of output. does not affect the level of aggregate supply in the long run. increases the level of aggregate supply in the long run only at very high levels of output.

The correct answer is: does not affect the level of aggregate supply in the long run.

Here's why:

1. The long-run aggregate supply (LRAS) is the total amount of goods and services that firms are willing and able to supply at a given level of technology and factor inputs (like labour and capital), irrespective of the price level.

2. In the long run, firms can adjust their production levels in response to (or in anticipation of) changes in demand and costs. This means they can change the quantity of inputs they use, enter or exit industries, build new factories, or introduce new technologies.

3. Therefore, changes in the price level do not affect the level of aggregate supply in the long run. This is because, in the long run, firms will adjust their production to the price level, so the quantity of goods and services they are willing and able to supply does not depend on the price level.

4. This is represented graphically by a vertical LRAS curve, which shows that the level of aggregate supply is the same at all price levels in the long run.