What is insulating tape primarily used for?

Insulating tape is primarily designed to provide insulation against electrical conductivity, making it essential in electrical work. Its primary function is to prevent electric current from passing through unintended paths, which could create hazards such as short circuits or electric shocks. When wrapped around wires and connections, insulating tape effectively isolates conductive materials, ensuring that electricity flows only where it is intended, thus maintaining safety and device functionality.

The other options present tasks that insulating tape is not primarily intended for. While it can bond surfaces and cover mechanical connections, these are secondary functions and not the main purpose. Marking electrical circuits is also not a primary use of insulating tape; specialized marking tapes or labels are typically employed for that purpose. Therefore, the main function of insulating tape aligns closely with its role in providing electrical insulation, making option C the correct choice.