Looking at the Impact of Television Viewing on Aggressive Behavior

looking at the impact of television viewing on aggressive behavior in nursery school children, it was found that children who had been rated high in aggression before the experiment behaved even more aggressively after repeated exposure to aggressive cartoons. The findings of this field experiment

A) demonstrate that all children become more aggressive when exposed to violent television.
B) can be more easily generalized to the real world than the findings of a laboratory experiment.
C) would probably be drastically different if conducted in a laboratory setting.
D) are invalid due to observer bias.