How does the caste system relate to Buddhism being an effective universalizing religion?

A Buddhism incorporated parts of the case system that gave Brahman authority over adherents.
B Buddhism embraced the caste system, excluding women from the ability to attain enlightenment
C Buddhism rejects the system that traditionally excludes parts of society
D buddhism rejected the system because it would make the king the head of the religion

C Buddhism rejects the system that traditionally excludes parts of society.