Suppose We Know That Among Caucasians in the United States

Suppose we know that among Caucasians in the United States, 50% of the difference in intelligence between one individual and the next is due to genetics. The textbook illustration of seeds growing in different soils is intended to suggest that __________.

A) we can assume that genetics is primarily responsible for any difference in intelligence between Caucasians and African Americans
B) we can assume that any difference in intelligence between Caucasians and African Americans is largely a matter of the environment
C) we can expect that genetics explains a similar proportion of the difference in intelligence between Caucasians and African Americans
D) we cannot assume that genetics assumes a similar proportion of the difference in intelligence between Caucasians and African Americans