Definition: You are given a question on high school macroeconomics. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: Which of the following best measures changes in the price level of national product?
(A)The consumer price index (B)The real interest rate (C)The unemployment rate (D)The GDP deflator

D