Which of the Following Most Accurately Describes the American Middle

Which of the following most accurately describes the American middle class between 1970 and 2015?

A) They have grown dramatically in number.
B) They have come to receive more than half the nation's income.
C) Their share of the nation's income has fallen by almost 20 percent.
D) Their numerical size and share of the nation's income have remained remarkably constant.
E) None of these answers is correct.