Data from more than 45 family and twin studies spanning seven decades of research point to the ...

Data from more than 45 family and twin studies spanning seven decades of research point to the following fact about the inheritability of schizophrenia:
 
  A) Schizophrenia inheritability has been found to have very little genetic basis.
  B) A person whose twin has schizophrenia has a 40 chance of having the disease.
  C) The risk of inheriting schizophrenia to relatives of someone who has the disorder is less than the risk to relatives of normal controls.
  D) Schizophrenia is known to be inherited through behavioral family pathology, not through genetic means.