Question

observe the static electric charge of the sweater. then choose the balloon that you would expect to see having the highest electrostatic field attraction to the sweater. move it closest to sweater to show the appropriate field interaction.

Explanation:

The sweater has positive static charge. For electrostatic attraction, the balloon should have negative charge (opposite charges attract). The balloon with the most negative charge (or highest magnitude of negative charge relative to the sweater's positive charge) will have the highest electrostatic field attraction. So we choose the balloon with negative charge (assuming available balloons have charges, the one with negative charge opposite to the sweater's positive will show strongest attraction).

Answer:

Choose the balloon with negative static electric charge (opposite to the sweater's positive charge) and move it closest to the sweater.