According to Family, Twin, and Adoption Studies, a Person Is

According to family, twin, and adoption studies, a person is at greatest risk for developing schizophrenia

A) if he or she has an identical twin diagnosed with the disorder.
B) if he or she has a nonidentical twin diagnosed with the disorder.
C) if he or she has an adoptive parent diagnosed with the disorder.
D) if he or she has a biological parent diagnosed with the disorder.
E) if he or she is adopted into a family with two schizophrenic siblings.