When two magnets with like poles facing each other are brought close together, they will experience a repulsive force due to the like poles. As they approach each other, work is done against this repulsive force, and energy is stored in the system due to the magnetic interaction.
When they are then released, the magnets will move apart due to the repulsion, which causes the stored energy to be converted into kinetic energy of the moving magnets.
Thus, the correct response would be: The energy stored decreases and then increases. This reflects the transition from stored potential energy in the magnetic field to kinetic energy as the magnets move apart.