Final answer:
The artifact caused by 60-cycle interference can be a result of all the mentioned factors: improperly grounded electrical equipment, crossing of cable wires with other wires, and frayed or broken wires.
Step-by-step explanation:
The artifact caused by 60-cycle interference can be a result of several factors including improperly grounded electrical equipment, crossing of cable wires with other electrical wires, and frayed or broken wires. As electricity from high-voltage AC power transmission lines operates at frequencies of 50 or 60 Hz, the long wavelength electromagnetic waves can produce electromagnetic induction which may cause interference. Key safety features designed to manage this include grounding the case of the appliance to keep the voltage near zero and prevent shock, as well as other preventive measures like the use of ground fault interrupters (GFIs) and isolation transformers to mitigate electrical hazards. Therefore, the correct answer to the question is that the artifact caused by 60-cycle interference can be due to all of the mentioned problems, all of the above.