Which Statement About Income Distribution in the United States Is

Which statement about income distribution in the United States is accurate?

A) There has been a large increase in the number of families earning more than $100,000 in recent decades.
B) Working-class families have enjoyed a significant increase in income since the 1970s.
C) Income is now distributed more equally than during previous decades.
D) The income of average families, adjusted for inflation, has increased significantly since the 1970s.