Answer:
D. Overstates; Understates
Explanation:
The CPI (Consumer Price Index) overstates the underlying inflation rate because when the price of a commodity rises, consumers tend
to purchase less of it and seek for
substitutes instead. Conversely, as the price of
a commodity falls, consumers tend to purchase more
of it. The above suggests that commodities with
generally rising prices would become less important in the stock of commodity used to calculate inflation, while commodities with falling prices would become more
important. In conclusion, CPI doesn't take into account that consumers can substitute commodities whose prices has risen with cheaper ones.
Also, the core inflation measures the more persistent underlying inflation rather than transitory influences on the price level thereby understating it.