What Does the Consumer Price Index Measure

Multiple Choice

What does the consumer price index measure?  

A)  the cost of a market basket of consumer goods and services relative to its cost in some base year 
B)  the change in the average price of a market basket of "necessary" goods and services 
C)  the annual inflation rate in the producers' goods market 
D)  the change in the average price level of all final goods and services