Why does the short-run aggregate supply curve shift to the left in the long run, following an increase in aggregate demand?

Why does the short-run aggregate supply curve shift to the left in the long run, following an increase in aggregate demand?

A) Workers and firms adjust their expectations of wages and prices downward and they accept lower wages and prices.

B) Workers and firms adjust their expectations of wages and prices downward and they push for higher wages and prices.

C) Workers and firms adjust their expectations of wages and prices upward and they push for higher wages and prices.

D) Workers and firms adjust their expectations of wages and prices upward and they accept lower wages and prices.

An explanation will be of help.