Behaviour Genetics Rests in Part on the Premise That, to the Extent

Behaviour genetics rests in part on the premise that, to the extent that environmental factors are important, individuals who _____ should be more similar than are individuals who _____.

A) are closely related; are unrelated
B) are unrelated; are closely related
C) have lived together; have not lived together
D) have not lived together; have lived together