The correct answer is option 'C' - Factor Reversal Test.

Explanation:
The factor reversal test is a method used to check the accuracy and consistency of price and quantity indices. In this test, the product of the price index and the quantity index is compared to the corresponding value index.

Here's a detailed explanation of the factor reversal test:

1. Price Index:
The price index measures the average change in prices of a basket of goods and services over time. It helps in understanding the inflation or deflation in an economy. The formula for calculating the price index is:
Price Index = (Current Price / Base Price) * 100

2. Quantity Index:
The quantity index measures the average change in the quantity of goods and services produced or consumed over time. It helps in understanding the changes in production or consumption levels. The formula for calculating the quantity index is:
Quantity Index = (Current Quantity / Base Quantity) * 100

3. Value Index:
The value index measures the average change in the value of goods and services produced or consumed over time. It takes into account both the price and quantity changes. The formula for calculating the value index is:
Value Index = (Current Value / Base Value) * 100

4. Factor Reversal Test:
According to the factor reversal test, if the product of the price index and the quantity index is equal to the corresponding value index, then it indicates that the calculations are accurate and consistent. In other words:
Price Index * Quantity Index = Value Index

If this equation holds true, it means that the changes in prices and quantities are correctly reflected in the value of goods and services.

5. Significance of the Factor Reversal Test:
The factor reversal test is important because it helps in validating the accuracy of price and quantity indices. If the test fails, it suggests that there may be errors in the calculations or discrepancies in the data. This can lead to incorrect conclusions about changes in the economy.

In conclusion, the factor reversal test is a valuable tool to ensure the accuracy and consistency of price and quantity indices. If the product of the price index and the quantity index is equal to the corresponding value index, it indicates that the calculations are correct. Therefore, option 'C' is the correct answer.