Concerning Marital Status and the Earnings of Women, Which of the Following

Concerning marital status and the earnings of women, which of the following is true?

A) Employers who discriminate against women will have lower costs than rival firms that hire employees strictly on the basis of merit (productivity) .
B) On average, the number of hours worked per year by women in the labor force is greater than the hours worked by men in the labor force.
C) The female/male earnings ratio is substantially higher for never married persons than for those married with a spouse present.
D) As the proportion of women preparing for careers as professionals has increased in recent decades, the earnings of women have declined relative to those for men.