Sora is testing how electric forces can change. She charges two rubber balloons with equal amounts of negative charge and places them 50 cm away from each other. Then, she uses a piece of wool to double the charge on one of the balloons, while keeping everything else the same. How does the electric force between the balloons change?
a. The electric force is reduced by half.
b. The electric force stays the same.
c. The electric force is doubled.
d. The electric force is quadrupled.