What inspections can certificated mechanics perform under their general certificate privileges?

A certificated mechanic with a general certificate is authorized to perform certain inspections under their privileges, and option C correctly identifies one of those tasks. Specifically, certificated mechanics can indeed conduct 100-hour inspections on instruments, as this falls within their scope of work related to the maintenance and upkeep of aircraft.

The 100-hour inspection is particularly relevant for aircraft that are utilized for hire and must be performed at regular intervals. Mechanics are trained to assess and maintain the equipment, ensuring that it operates safely and efficiently. This aligns with their role in contributing to the overall airworthiness of the aircraft.

The other options, while relating to maintenance tasks that might be performed by mechanics, extend beyond the capabilities of a general certificate holder. For example, annual inspections require a more specific set of certifications and are typically performed by an Airframe and Powerplant (A&P) mechanic with Inspection Authorization (IA), which is not a level of certification covered under general privileges. Hence, only option C accurately reflects the capabilities of certificated mechanics regarding inspections.