What Is One of the Main Conclusions from Adoption Research

What is one of the main conclusions from adoption research concerning the effects of genes and environment on personality?

A) Being raised together doesn't lead to much similarity in personality between parents and offspring.
B) The environmental influences of the adoptive home exert a stronger influence on personality than genetic ones.
C) Adopted children are more similar to their adoptive parents,but only if they were adopted prior to the age of 2.
D) Personality traits of biological parents are unrelated to the personality traits of children they gave up for adoption.