Answer:
The correct answer is option c.
Explanation:
In an economy, in the long run, the aggregate supply is fixed. The aggregate supply curve is a vertical line. This is because, in the long run, supply remains unaffected by price level. The increase in product price is balanced by an increase in input prices. So the supply does not change with change in the price level.
In the long run, the supply changes with change in the availability of resources and change in technology. So when the aggregate demand declines, the demand curve shifts to the left. The equilibrium quantity remains the same but the price level declines.
It is also evident in the figure attached.
