This is the index of prices of a given basket of commodities which are bought by the representative customer. Two years under consideration are kept - one is the base year, the other is the current year. First, the cost of purchase of a given basket of commodities in the base year is calculated. Then the cost of purchase of the same basket in the current year is calculated. Then we express the latter as a percentage of the former.

This index is called:

Consumer Price Index

The correct answer is Option (3) → Consumer Price Index

Consumer Price Index (CPI):  This is the index of prices of a given basket of commodities which are bought by the representative consumer. CPI is generally expressed in percentage terms. We have two years under consideration – one is the base year, the other is the current year. We calculate the cost of purchase of a given basket of commodities in the base year. We also calculate the cost of purchase of the same basket in the current year. Then we express the latter as a percentage of the former. This gives us the Consumer Price Index of the current year vis-´a-vis the base year.