According to Family Pedigree and Twin Studies, a Person Is

According to family pedigree and twin 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.