Answer:
Increase.
Step-by-step explanation:
The force between two charges is given by :
![F=(kq_1q_2)/(d^2)](https://img.qammunity.org/2022/formulas/physics/high-school/7lbwb7jwxo97hub2cz295y2zc95ms1oxd9.png)
Where
k is electrostatic constant
d is the distance between two charges
The force is inversely proportional to the distance between charges. It means when the distance between two charges decreases, the electric force will increase. Hence, the correct option is (c) "increase".