The correct answer is:
The balloons will hang at a greater elevation, because they will have greater charges so the force of electrical repulsion between them will be greater.
When Bobby rubs the balloons with animal fur, it causes the transfer of electrons between the balloons and the fur, resulting in the balloons becoming charged. The rubbing process increases the amount of charge on the balloons. Since like charges repel each other, the increased charge on the balloons will create a stronger repulsive force between them. As a result, the balloons will hang at a greater elevation, moving further apart from each other.