In a Twin Study, an Investigator Compares Concordance Rates of Fraternal

In a twin study, an investigator compares concordance rates of fraternal and identical twins. A concordance rate is best described as

A) the degree of genetic similarity between the twins.
B) the degree of environmental similarity between the twins.
C) the degree to which twins resemble their parents.
D) the percentage of shared traits or disorders.
E) the percentage of genetic overlap.