Which of the Following Statements About Studies Assessing Rates of Schizophrenia

Which of the following statements about studies assessing rates of schizophrenia across countries is true?

A) Incidence rates of schizophrenia do not vary much from country to country.
B) Patients with schizophrenia in less-developed countries tend to fare better over time than those from more developed countries.
C) People who presented with psychotic symptoms that were inconsistent with a diagnosis of schizophrenia were not included in the studies.
D) Subtypes of schizophrenia vary substantially from country to country.
E) All of these statements are true.