Concept:Like charges repel each other, so bringing them closer requires external work against the repulsive force.
Explanation:Two like charges always exert a repulsive force on one another.
To reduce the distance between them, an external agent must push them together against this repulsion.
This means work is done against the electric field of the charges.
The energy spent in doing this work is stored in the system as electric potential energy.
Thus, as the like charges are brought closer, the potential energy of the system increases.
The increase happens because work is done against the field, not by the field.
Therefore, the correct choice is the one that states potential energy increases due to work done against the field.
Answer:Option A: increase because work is done against the field.