Which of the Following Statements Is True of the Gorby

Which of the following statements is true of the Gorby study?

A) South American, Central American and Middle Eastern countries combined accounted for the largest percentage of serial killers in his data analysis.
B) Since 1900 the percentage of European cases has declined steadily while just the opposite is occurring in non-European countries.
C) There were fewer female serial killers in the Gorby study than in the Hickey study.
D) Compared to the Hickey study, there were far fewer cases of serial murder in the Gorby study where offenders had an accomplice.