Which of the Following Statements Is True of an Achievement

Which of the following statements is true of an achievement gap?

A) Fifty years ago, the largest achievement gap was between social classes.
B) It refers to the difference in earnings that occurs due to age-related differences.
C) The achievement gap between children from high- and low-income families has reduced since the 1960s.
D) Achievement gaps among minority groups are due to factors like English language proficiency and social class.
E) It is overemphasized by functional theorists.