After Graduating from University, Mary Took a Job at a Daycare

After graduating from university, Mary took a job at a daycare centre, while her friend Paul took a job as a landscaper. Mary was shocked at how much more Paul was paid, given their similar education level. According to the text, what is one explanation for this pay difference in our society?

A) Women encounter the glass ceiling immediately after university.
B) Men are better at negotiating a high salary.
C) Paul needed more skills and this was reflected in his salary.
D) The skill set commonly associated with women (e.g., nurturing) is undervalued.