Why Are Adoption Studies Often Used When Attempting to Study

Why are adoption studies often used when attempting to study the influence of genetic factors on psychological disorders?

A) They allow examination of genetic influences of psychopathology using more sophisticated statistical techniques.
B) They allow examination of genetic influences of psychopathology without the typical confound of having siblings raised in the same environment.
C) They allow examination of genetic influences of psychopathology without the typical confound of common biological parents.
D) They allow examination of genetic influences of psychopathology through direct examination of genetic causes.