The Single Most Important Phenomenon in the U

The single most important phenomenon in the U.S. labor market in the second half of the 20^th century was

A) the drastic reduction in the labor force participation rate of males.
B) the drastic increase in the labor force participation rate of females.
C) the elimination of the glass ceiling.
D) the increase in the average number of hours worked each week.
E) the elimination of child poverty.