Answer: Option (D) is correct.
Explanation:
If the potential GDP is 70 and economy is in recession. Potential GDP is the GDP of an economy which can be achieved with the best utilization of economy's resources.
The amount of the shortfall in planned aggregate expenditure is equal to the vertical distance between the 45 degree line and the AE = Y, at a level of potential real GDP.
This is also shown by an arrow in the diagram.