Which of the following is correct?
a. Discretionary fiscal policy is an endogenous reaction to output gaps
b. Real GDP is the variable most commonly used to measure short run economic fluctuations. These fluctuations can be predicted with a high degree of accuracy.
c. Nominal GDP is the variable most commonly used to measure short-run economic fluctuations. These fluctuations can be predicted with a high degree of accuracy.
d. Capacity utilisation tends to be a good indicator of potential inflation and unemployment