Studies Relating Rates of Diagnosis of Schizophrenia to Poverty and Race

Studies relating rates of diagnosis of schizophrenia to poverty and race show:

A) a connection between diagnosis of schizophrenia and poverty.
B) a connection between diagnosis of schizophrenia and race.
C) a connection between diagnosis of schizophrenia and both race and poverty.
D) no clear connection between diagnosis of schizophrenia and either race or poverty.