What fundamental economic concept distinguishes nominal GDP from real GDP.
a. Nominal GDP is used to measure an economy's output, while real GDP is a concept only applicable to financial transactions and investments.
b. Nominal GDP is always lower than real GDP because it accounts for future expectations.
c. Real GDP is the total value of goods and services produced, while nominal GDP represents only the inflation adjusted economic output.
d. Nominal GDP is the total value of goods and services produced in a country in current market prices, while real GDP adjusts for inflation and deflation, which provides a measure of output in constant prices.