What type of warning does a prusik hitch provide when overloaded?

A prusik hitch provides an overload warning through its inherent design and behavior when under excessive load. When a prusik is overloaded, it may begin to slip or fail, which signals to the rescuer that the load exceeds the safe working capacity of the knot. This slippage acts as an immediate indication that adjustments need to be made, either in load distribution or the rescue system's setup.

In contrast, the other options do not accurately represent the nature of the warning provided by a prusik hitch. While visual and audible warnings are common in other safety mechanisms or equipment, the prusik hitch's warning comes exclusively as a result of its operational failure to grip under load, making it a unique alert system tailored to the specific dynamics of rope rescue operations. Therefore, the answer properly identifies the functional ability of the prusik hitch in the context of technical rescue scenarios.