Is Having a Gender Variant Identity More Likely Caused by Nature-

Is having a gender variant identity more likely caused by nature- or nurture-related factors?

A) Nature.Gender variant disorder almost always reflects hormonal abnormalities.
B) Nurture.Gender variant disorder almost always stems from abusive or pathological parenting.
C) Gender variant disorder probably reflects an interaction between nature and nurture.
D) Psychologists have not examined gender variant disorder enough to know.