Which components should be checked during a pre-trip inspection?

The correct choice highlights important components to check during a pre-trip inspection, specifically the engine oil level and seat belt fastener. Checking the engine oil level is crucial as it ensures the engine has adequate lubrication, preventing overheating and wear, which can lead to serious mechanical failures during a trip. The seat belt fastener is equally important as it guarantees the safety of the driver and any passengers, ensuring that safety equipment is functioning correctly before driving.

While other options include important vehicle components, they each focus on a narrower range of checks. For instance, checking rearview mirrors and headlights is essential for visibility and safety on the road, whereas tire pressure and wiper fluid are vital for handling and visibility during inclement weather. Lastly, brakes and fuel gauge are fundamental for safe operations as well, but the chosen answer encompasses critical drivetrain health and passenger safety equipment, making it a comprehensive selection for a pre-trip inspection.