Suppose the Okun's law coefficient is 2, the full-employment level of output is $5000 billion, and the natural rate of unemployment is 6%. (a) What is the current level of output if the current unemployment rate is 8%? (b) Suppose the unemployment rate falls to 5%; what is the current level of output? (c) Suppose structural changes in the economy raise the natural rate of unemployment to 7%, and lower the full-employment level of output to $4800 billion. If the current unemployment rate is 8%, what is the current level of output?