Which of the following is the correct formula for calculating the consumer price index?
a. [(CPI in year 1- CPI in year 2) / CPI in year 2] x 100
b. [(price of basket of goods and services in current year / price of basket in base year)] x 100
c. [(price of basket of goods and services in current year - price of basket in base year) / price of basket in base year ] x 100
d. [(price of basket of goods and services in base year / price of basket in current year)] x 100
