Answer:
c) P3, Q3.
Step-by-step explanation:
The new long run equilibrium point will be where the aggregate demand curve 1 (AD1) intersects long run aggregate supply curve (LRAS) at P3, Q3.
Since the LRAS curve is horizontal at Q3, all the equilibrium points must be located at Q3, so all you have to check is at what price the AD curve intersects Q3.