Which of the Following Is Most True of the Relationship

Which of the following is most true of the relationship between an individual's income and his or her voting behavior?

A) Low-income people tend to vote more Democratic than Republican.
B) Upper-income people almost always vote Democratic.
C) Upper-income people are less likely to vote than lower-income people are.
D) An individual's income is almost completely unrelated to his or her voting behavior.