Why does the self-correcting mechanism stop working when the policy rate hits the zero lower bound? a. the self-correcting mechanism stops working because the rising inflation produced by a negative output gap produces lower rather than higher real interest rates when the policy rate hits the zero lower bound, and this decrease depresses planned spending and further widens the output gap. b. the self-correcting mechanism stops working because the falling inflation produced by a negative output gap produces lower rather than higher real interest rates when the policy rate hits the zero lower bound, and this decrease depresses saving and investment and therefore further widens the output gap. c. the self-correcting mechanism stops working because the falling inflation produced by a negative output gap produces higher rather than lower real interest rates when the policy rate hits the zero lower bound, and this increase depresses planned spending and further widens the output gap. d. the self-correcting mechanism stops working because the rising inflation produced by a positive output gap produces lower rather than higher real interest rates when the policy rate hits the zero lower bound, and this decrease enhances planned spending and further widens the output gap.