Adoption Studies Provide a Rich Setting for Discriminating Between the Contributions

Adoption studies provide a rich setting for discriminating between the contributions of genetics and environment on behaviour. In such a study, which of the following would indicate an environmental influence on behaviour?

A) An adoptive parent selects a child to adopt who is similar in temperament.
B) An adopted child is more similar in behaviour to a biological parent than to an adoptive parent.
C) The adopted child and the adoptive parent are similar in a behavioural trait.
D) An adoptee in a selective placement is similar in behaviour to the adoptive parent.