**Explanation:**

The correct answer is option D - Laspeyres Method.

**Laspeyres Method:**
The Laspeyres method is one of the methods used to construct the Consumer Price Index (CPI). It is named after the German economist Ernst Louis Laspeyres. The method is a fixed-weight index formula, meaning that it uses a fixed basket of goods and services to calculate the index.

**Steps involved in the Laspeyres Method:**

1. Selection of Base Year: A base year is chosen as a reference period. The prices of goods and services in this year are used as a benchmark for comparison with subsequent years.

2. Selection of a Basket of Goods: A representative basket of goods and services is selected based on their importance in the consumer's budget. This basket typically includes items such as food, housing, transportation, healthcare, and education.

3. Determining the Quantity and Price of Goods: The quantities and prices of goods and services included in the basket are determined for the base year. This information is usually obtained through surveys and market research.

4. Calculating the Index for Subsequent Years: The quantities of goods and services in the basket are held constant, while their prices in subsequent years are recorded. The index is calculated by dividing the total cost of the basket in a particular year by the total cost of the basket in the base year and multiplying by 100.

**Advantages of the Laspeyres Method:**

- Easy Calculation: The Laspeyres method is relatively simple and straightforward to calculate.
- Historical Comparisons: The use of a fixed basket of goods allows for meaningful comparisons over time, as the same goods and services are being compared.

**Limitations of the Laspeyres Method:**

- Substitution Bias: The Laspeyres method does not account for changes in consumer behavior, such as substituting goods and services when their prices change. This can lead to an overestimation of inflation.
- Quality Changes: The method does not account for changes in the quality of goods and services over time, which can affect the accuracy of the index.

In conclusion, the Laspeyres Method is used for constructing the Consumer Price Index (CPI). It involves selecting a base year, determining a basket of goods, calculating the index based on fixed weights, and comparing subsequent years' prices to the base year. While it has advantages in terms of ease of calculation and historical comparisons, it also has limitations related to substitution bias and quality changes.