What Might Be a Reason for the Term Miscegenation Being

What might be a reason for the term miscegenation being a demeaning word?

A) Racist thinking demands adherence to a strict social standard that hinges entirely on correctness of skin color,so intermarriage would violate this social norm.
B) Racist thinking often conflates human beings with nonhuman animals,so intermarriage might mean marriage to nonhuman species.
C) Racist thinking structures a society around a particular kind of social order with whites and nonwhites kept physically separate,so intermarriage would allow physical mixing.
D) Racist thinking organizes social boundaries along the lines of descent,thus intermarriage would confuse ancestral lineage and paternity.