Which of the following is held constant when constructing a production possibilities curve?

Research on the effects of recessions on the real level of GDP shows that

A) recessions cause only temporary reductions in real GDP, which are offset by growth during the expansion phase. B) recessions cause large, permanent reductions in the real level of GDP. C) recessions cause both temporary and permanent declines in real GDP, but most of the decline is temporary. D) recessions cause both temporary and permanent declines in real GDP, but most of the decline is permanent.

Policymakers' attempts to use the Phillips curve to reduce the unemployment rate below the natural rate

A) will be successful since the Phillips curve shows the relationship between the inflation rate and the unemployment rate. B) will be successful if monetary policy is used. C) will be unsuccessful if monetary policy is used since monetary policy leads to higher prices. D) will be unsuccessful since workers' expectations adjust to attempts to reduce unemployment below the natural rate.