When a group of children who have been watching television programs that include acts of violence is sent to play with a group of children who have been watching programs that do not include acts of violence, the children who have been watching violent programs commit a much greater number of violent acts in their play than do the children who have been watching nonviolent programs.
Your task
Find the assumption the argument requires in order for its conclusion to hold.
Common trap
Answers that would help the argument but aren't strictly required (sufficient, not necessary).
Winning move
Negate each choice — the right one breaks the argument when negated.