What will happen to the equilibrium price level and the equilibrium quantity of output in the short run if the aggregate demand curve shifts to the right? short run. so use SPAS) )a. The equilibrium price level and the equilibrium quantity of output decrease. Q b. The equilibrium price level increases while the equilibrium quantity of output decreases. c. The equilibrium price level increases while the equilibrium quantity of output remains unchanged. d. The equilibrium price level and the equilibrium quantity of output increase