Which Statement Is TRUE with Respect to Short-Run and Long-Run

Multiple Choice

Which statement is TRUE with respect to short-run and long-run aggregate supply?

A) The economy can be on both curves simultaneously.
B) If the economy is on the short-run aggregate supply curve, it cannot also be on the long-run aggregate supply curve.
C) If the economy is on the long-run aggregate supply curve, it cannot also be on the short-run aggregate supply curve.
D) The economy can never rest on both curves simultaneously.