The Spider’s Web

A question on the LSAT, first:

Poor nutrition is at the root of the violent behavior of many young offenders. Researchers observed that in a certain institution for young offenders, the violent inmates among them consistently chose, from the food available, those items that were low in nutrients. In a subsequent experiment, some of the violent inmates were placed on diet high in nutrients. There was a steady improvement in their behavior over the four months of the experiment. These results confirm the link between poor nutrition and violent behavior.

Then:

Which one of the following, if true, most strengthens the argument?

1. Some of the violent inmates who took part in the experiment had committed a large number of violent crimes.
2. Dietary changes are easier and cheaper to implement than any other type of reform program in institutions for young offenders.
3. Many young offenders have reported that they had consumed a low-nutrient food sometime in the days before they committed a violent crime.
4. A further study investigated young offenders who chose a high-nutrient diet on their own and found that many of them were nonviolent.
5. The violent inmates in the institution who were not placed on a high-nutrient diet did not show an improvement in behavior.

Well, what do you think is the correct answer and, if you like, why? Bonus question: how many of the Wall Street Occupiers do you think would be able to answer this question and get the wrong answer?