Researchers Found That in the United States and Canada,homicide Rates

Researchers found that in the United States and Canada,homicide rates doubled during the period in which TV was introduced.This finding does not prove that viewing violence on TV causes aggression because

A) the finding could not be replicated in another country.
B) the researchers randomly assigned viewers to watch either violent or nonviolent programming.
C) the research finding involved correlational evidence.
D) the research participants knew they were part of an ongoing TV viewing study.