In a recent study on the connection between brain abnormalities and violent behavior, the researcher examined more than three hundred people who had engaged in unusually violent behavior toward friends and family members. In most of the people studied, the researcher found clues of brain abnormalities, including evidence of past brain injury and physical abnormality. The researcher concluded that evidence of brain abnormalities could be used to predict violent behavior.
Which of the following, if true, would most seriously weaken the researcher’s conclusion
A．The incidence of brain abnormalities in the general population is as high as that in the group examined.
B．The brain abnormalities discovered in those studied are of two distinct kinds.
C．A wide variety of violent actions were exhibited by those studied.
D．Those studied in the experiment acted violently toward strangers as well as toward people they knew.
E．(E) The study drew its subjects from a large geographical area.