19. Assume that the MPC is 0.8. Assume that the total crowding-out effect is $25 billion. How will an increase in government purchases of $9 billion shift the AD curve? a. It will shift the AD curve right by $25 billion. b. It will shift the AD curve left by $25 billion. c. It will shift the AD curve right by $20 billion. cl. It will shift the AD curve left by $20 billion