Which of the following is the definition of the Consumer Price Index (CPI)?
A. A weighted average of prices of a market basket of goods and services purchased by typical urban consumers.
B. A statistical measure of average prices using annually updated weights based on surveys of consumer spending.
C. A broad price index measuring the changes in prices of all new goods and services produced.
D. A statistical measure of a weighted average of prices of goods and services that firms produce and sell.