Which of the following is an example of pilot-performed preventative maintenance?

Changing oil is a prime example of pilot-performed preventative maintenance. This task is specifically included under the scope of preventative maintenance that pilots can carry out on their aircraft, as outlined in FAA regulations. Regular oil changes are crucial for the maintenance of an aircraft's engine, ensuring proper lubrication and helping to prevent wear and tear, which in turn contributes to the overall safety and reliability of the aircraft.

In contrast, tasks such as engine overhauling or installing new avionics typically require specialized skills and extensive knowledge beyond what is expected of a pilot. These procedures are often performed by licensed A&P (Airframe and Powerplant) mechanics due to their complexity and the need for specific tools and equipment. Aircraft painting also involves a variety of skills and considerations concerning surface preparation and the application of different types of paint, and usually falls outside the realm of tasks that pilots are authorized to perform.