Robert Is Taking a Black History Class

Robert is taking a black history class.He learned that the one-drop rule labeled anyone who had a black ancestor as black.He concluded,based on this definition,that this was a racist rule.What is the best explanation as to why Robert would arrive at that conclusion?

A) When the one-drop rule became enshrined,blacks in the United States were slaves,a source of free labor;it was in the best interest of white Americans to increase the numbers of the enslaved.
B) By labeling people of mixed ancestry as black,whites in the American South could successfully increase their proportional representation in the U.S.Congress.
C) Social rules determine how we classify people by race and even when we know it is wrong.
D) Natural biological rules about race had yet to be postulated.