What does the author mean by "women are steadily chipping away at the glass ceiling" in Pa

What does the author mean by "women are steadily chipping away at the glass ceiling" in Paragraph One？

A．Nowadays full-time women are earning much more money than full-time men.

B．Full-time women are making hard efforts on jobs like walking at the glass ceiling.

C．Women are in dangerous condition, for their earnings are increasing too faster.

D．The gender pay gap is narrowing down, for women"s earnings are increasing gradually.

请帮忙给出正确答案和分析，谢谢！