One Reason for the Increase in Female Labor Force Participation

One reason for the increase in female labor force participation over the past fifty years is that

A) there has been an increase in the demand for blue-collar work.
B) many women now postpone family formation to complete their education and establish themselves in the labor force.
C) there has been no increase.
D) men have significantly reduced their labor force participation to engage in caregiving,so women have had to significantly increase their participation to compensate.