Answer:
Option D, Voter Turnout by Income Group, 2008
Explanation:
The graph has two variable - at x axis - income of the voters and at the other i.e the Y axis - Percentage of voters in a given income group.
Hence, the graph is a depiction of total % of people voting in a given income group.
The best title of the graph could be something which indicates the variation of % voting with respect to the income of the voters.
Hence, option D is the correct choice of answer
