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: In the United States over the years V and Q
(A)have not changed significantly. (B)are perfectly constant. (C)have decreased significantly. (D)have increased significantly.

D