Final answer:
The electric force between charges increases as the charge becomes stronger, due to the force being proportional to the product of their magnitudes. This force also increases when opposite charges are close together, as they more strongly attract each other. Thus, option c is correct.
Step-by-step explanation:
In physics, the electric force between charges is described by Coulomb's Law, which states that the force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. As a charge becomes stronger, the force exerted on nearby charges will increase. If the charges are of opposite signs, they will attract each other more strongly; if they are like charges, they will repel with greater force.
It is also important to note that the arrangement of charges can affect the net force. For instances when charges are distributed over an area, there will be a concentration of charge on the side closest to an oppositely charged object, which can further increase the net force on that object. This is due to the fact that electric fields generated by each charge can overlap and combine, magnifying the overall electric force.