Answer:
See explanation
Step-by-step explanation:
Potential energy here refers to energy that exists as a result of the relative position of the particles in a system.
Between figures 1 and 2 the potential energy of the system increases since the like charges repel when the distance between them is reduced.
Similarly, between 3 and 4, the potential energy of the system decreases since like charges attracts each other. Potential energy is inversely proportional to the force of attraction between the opposite charges hence potential energy decreases with decrease in distance.
The potential energy of the system decreases even more when one charge is +2 and the other is -1.