Answer
in general, americans with high incomes vote at
a) the same rate as any other income group
b) a lower rate than any other income group
c) a higher rate than those earning less money
d) a lower rate than those earning less money

C) a higher rate than those earning less money

Explanation:

Political scientists all over the globe have come to the conclussion that voter turnout has a direct correspondance to the income, the higher the income, the more politicallh involved the person becomes, this could also be related to the education, as a higher income is closely related to a higer education, more educated people and wealthier people tend to vote more.

it increase by 12% a year from 1812-1820