Which Statement Concerning Ethnicity and Intelligence Is MOST Accurate

Which statement concerning ethnicity and intelligence is MOST accurate?

A) The recent discovery of a "smart gene" has led most to believe that intelligence has a strong genetic component.
B) Even if ethnic groups differ significantly in intelligence, the difference could be the result of environmental factors.
C) Being economically disadvantaged is related to ethnicity but not to intelligence.
D) If intelligence differences within an ethnic group are due to genetics, then intelligence differences between the group and other ethnic groups must be due to genetics.