Which Is a Common Criticism of Twin Studies

Which is a common criticism of twin studies?

A) Twin studies are better suited to identify environmental influences than genetic influences.
B) Fraternal twins tend to be treated more similarly than identical twins.
C) Twin studies overestimate the role of prenatal experiences on devOBJ:pment.
D) Similarity in environmental experiences, not genetic similarity, may be the more important contributor to the similarity seen in twins.