Answer:
b. Real variables have been adjusted for changes in prices.
Explanation:
Nominal GDP = output × current year prices.
Real GDP = output × base year prices.
Nominal GDP is calculated using current year prices, therefore, the prices change overtime due to inflation. An increase in nominal GDP doesn't automatically mean we have produced more. It might mean price increased. It is when output increases that we have produced more.
Real GDP has been adjusted for inflation or changes in price. Real GDP is calculated using prices that do not change over time.
I hope my answer helps you
