Choice "A" is correct. The inflation rate measures the rate of increase in the overall price level in the economy.
Choice "d" is incorrect. The inflation rate is associated with price level changes not changes in the nominal value of output.
Choice "b" is incorrect. Inflation refers to a sustained increase in the overall price level. Not the price of a particular good.
Choice "c" is incorrect. The inflation rate is associated with price level changes not interest rate changes.
