Which of the Following Types of Research Would Be Very

Which of the following types of research would be very useful for examining the heritability of a particular trait?

A) Family studies, where researchers examine the extent to which a trait "runs" or goes together in intact families, those in which all family members are raised in the same home.
B) Twin studies, where researchers investigate whether fraternal twins are more alike on a psychological characteristic, like intelligence or extraversion, than are fraternal twins, and thus can infer that this characteristic is genetically influenced.
C) Adoption studies, where adoption agencies frequently place children in homes similar to those of the biological parents.
D) Phenotype studies, where individuals are tracked over time to find out whether their eventual phenotype is consistent with their phenotype at birth.