In the Nineteenth Century Supposedly "Scientific" Theories on Racial Differences

In the nineteenth century supposedly "scientific" theories on racial differences indicated that

A) blacks and whites were intellectually and morally equal.
B) blacks were less likely than whites to become drunkards and thieves.
C) whites and blacks were actually two separate species.
D) it was impossible to determine the causes of the physical and mental variations among human beings.
E) All races are equal.