The best statement describing how this demonstrates Newton’s third law is:
The trampoline pushes back with equal force but in the opposite direction.
This statement accurately reflects the principle that for every action, there is an equal and opposite reaction, as stated in Newton's third law. When the person jumps down on the trampoline, they exert a force on the trampoline, and in response, the trampoline exerts an equal and opposite force that propels the person upwards.