Final answer:
Option (B), Energy is released when two oppositely charged particles come closer together because the system's potential energy decreases due to the attractive electrostatic force, leading to the release of energy in the form of heat or light.
Step-by-step explanation:
When two oppositely charged particles become closer together, energy is released. This occurs because the system loses potential energy as the particles move closer due to the electrostatic force of attraction between them. When two like charges are brought closer, you must do positive work against the electrostatic force of repulsion, and this increases the system's potential energy. However, bringing opposite charges closer does not require work to be done against the electrostatic force since they naturally attract, causing the potential energy to decrease and therefore releasing energy.
For the charges described in the questions, as you bring a positive and a negative charge closer, the system's potential energy becomes more negative, leading to a release of energy, typically in the form of heat or light. This concept also explains why a concentration of charge increases the net force between distributed charges when they are close to an oppositely charged object. Furthermore, in the question about the positively charged particle exerting an inward force on particle P, particle P would be positively charged, indicating like charges repel each other.