What Is the Primary Methodological Advantage of Investigating the Link

What is the primary methodological advantage of investigating the link between mental disorder and crime in total birth cohorts?

A) These studies tend to be conducted in Scandinavian countries.
B) These studies avoid the problem of biased samples.
C) These studies ensure the mental disorder is not influenced by historical events.
D) These studies use official records for information about criminal behaviour.
E) These studies eliminate prenatal complications as a possible third variable.