Final answer:
A surge protector is used to prevent power surges from damaging electronic devices by blocking or grounding voltages above a safe level.
Step-by-step explanation:
A device that is inserted between the power supply and the outlet to protect the system from power surges is a d) Surge protector. A surge protector works by limiting the voltage supplied to an electric device by either blocking or shorting to ground any unwanted voltages above a safe threshold. This is crucial for protecting computers and other sensitive electronic equipment from the potentially damaging effects of voltage spikes.