Final answer:
The motion-detecting exterior light is an example of a closed system as it does not exchange matter with its surroundings, only energy.
Step-by-step explanation:
A closed system is one that can exchange energy but not matter with its surroundings. Out of the given options, the motion-detecting exterior light is an example of a closed system. Once the light has been started, all of the energy in the system remains there, and none is brought in from outside or leaves.