Which research question would be most appropriate for a four- to five-page research paper?

How many children between the ages of 5 and 10 acted out in school due to violent television in the year 2009?
How many children will have behavioral disorders due to violent television in the next ten years?
Is there a link between hours of television viewing and violent behavior in children aged 5 to 10?
Have crime rates increased in the US since television was invented?