Answer:
d. an increase in the overall level of prices in the economy.
Step-by-step explanation:
Inflation is a measure used to analyse the variation of the prices of determined products or/and services in a period of time.
In a normal economy, inflation tends to rise every period; which means that the purchasing power of people decreases.
E.g. Last year you bought a pencil for $3; however, the same pencil this year is $3.3. So, you have to get more money to buy the same pencil, which means that the money has lost a part of its value.