Which of the Following Statements About Behavioral Genetics Is True

Which of the following statements about behavioral genetics is true?

A) Genetic markers explain nearly all of the variation in human behavior.
B) Scientists have determined that heredity plays a larger role than the environment in human development.
C) A growing number of researchers regard the question of how much heredity and environment contribute to differences among people as unanswerable.
D) Researchers use heritability estimates to infer the role of the environment in complex human characteristics.