One of the Issues That Complicates the Interpretation of Twin

Multiple Choice

One of the issues that complicates the interpretation of twin studies is that

A) fraternal twins are usually perceived as a "set" and play together more often than identical twins do.
B) identical twins represent a more active type of genotype-environment correlation.
C) the environments of identical twins are more similar than those of fraternal twins.
D) fraternal twins are rarely studied in comparison to identical twins.