The correct answer is D) gender-based.
It showed that her workplace is not gender based.
Lily is arguing that she suffers discrimination because she has the position of supervisor but she is not earning the same amount of money that other supervisor that are men. She has been in the company for a while and has the same capacity as the other men that are doing the same job. That is why she says that his workplace is not gender based.
Gender-based companies give equal job opportunity to men and women and don't discriminate on gender, race or nationality. Men and woman have the same rights, privileges, and responsibilities.