Which of the following denotes a safety feature in electric circuits?

A fuse serves as a critical safety feature in electric circuits by providing overcurrent protection. Its primary purpose is to prevent excessive current from flowing through the circuit, which can cause overheating and potentially lead to fires or equipment damage. When the current exceeds a predetermined level, the fuse will melt and break the circuit, thus stopping the flow of electricity and protecting the circuit components from damage.

In contrast, the other options serve different functions. A disconnector is used to isolate a circuit for maintenance or safety but does not inherently protect against overcurrent. A contactor is an electrically controlled switch used for controlling power circuits, usually under normal load conditions. Meanwhile, a relay is a switch that is activated by an electrical signal, often used for control purposes rather than direct safety protections. While all these components have their roles in an electric system, the fuse specifically targets safety against overcurrent conditions.