Which Statement Describes Evidence of the Importance of Environmental Factors

Which statement describes evidence of the importance of environmental factors in the development of a particular trait?

A) An adoptive twin study shows that the correlation between identical twins who grew up together is higher than the correlation between identical twins who grew up apart.
B) A twin study shows that the correlation between identical twins is higher than the correlation between fraternal twins.
C) An adoption study shows that the correlation between adoptive children and their biological parents is higher than the correlation between the children and their adoptive parents.
D) All of the statements describe such evidence.