Answer:
A). to track monthly changes in prices paid by urban consumers.
Explanation:
CPI(Consumer Price Index) is characterized as 'a statistical estimate of the price level of goods and services bought by consumers for consumption purposes by the households.' It primarily aims to estimate the change or swap in the prices of the weighted average price of the common basket(consumption goods, as well as, services that the consumers pay for). It is calculated using the formula;
[tex]CPI_{t} = \frac{C_{t} }{C_{0} } * 100[/tex]
where,
[tex]CPI_{t}[/tex] = current Consumer Price Index
[tex]C_{t}[/tex] = Current price basket
[tex]C_{0}[/tex] = Cost of price basket in the base year
It assists in deducing whether the average prices have received a fall or rise and determines inflation or deflation. Thus, option A is the correct answer.