Questions: d) is a method for calculating changes in real GDP which uses an early base year and a late base year.

The answer is option d: is a method for calculating changes in real GDP which uses an early base year and a late base year.

Explanation for each option:

a) Incorrect. Chained dollars are not used to convert real GDP to nominal GDP. Instead, they are used to adjust nominal GDP to account for inflation, providing a more accurate measure of real GDP over time.

b) Incorrect. The money that banks are required to keep in their vaults to back deposits is known as reserves, not chained dollars.

c) Incorrect. Chained dollars are not a measure for the value of intermediate goods. They are used to measure real GDP by adjusting for inflation.

d) Correct. Chained dollars are a method for calculating changes in real GDP. This method uses a chain-weighted index that incorporates both an early base year and a late base year to provide a more accurate reflection of economic growth by accounting for changes in the relative prices of goods and services over time.

In summary, chained dollars are used to calculate changes in real GDP by employing a method that uses both an early and a late base year to adjust for inflation and changes in relative prices.