Answer: The correct option is A.
Step-by-step explanation:
The electric potential energy is defined as the work done required in assembling the charges by bringing them close together.
The kinetic energy is due to the motion of the particle.
In the given problem, a proton is moving towards a stationary charged particle. There will an energy change that could occur as the particles get closer.
The moving charge gains electric potential energy and losses its kinetic energy until it stops.
At that point, Kinetic energy will be converted into electric potential energy if the stationary particle is positive.