Answer: option c) the electric force between them decreases.
Step-by-step explanation:
The electric force that two charged objects exert on each other follows Coulomb's law: the electric force is proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance that separate the charges.
Mathematically, that is:
Hence, you conclude that if the distance between the charges is increased, the electric force will decrease.