During a pre-trip inspection, which fluid levels should be checked?

The correct choice emphasizes the importance of checking oil, coolant, and transmission fluid during a pre-trip inspection, which is essential for safe vehicle operation.

Oil is critical for lubricating the engine components, reducing friction, and preventing overheating. Ensuring that the oil level is adequate helps maintain engine health and performance.

Coolant plays a vital role in managing the engine's temperature. Checking the coolant level ensures that the engine will not overheat during operation, which could lead to severe mechanical failures.

Transmission fluid is essential for the proper functioning of the transmission system, as it lubricates the gears and assists in cooling. Adequate transmission fluid levels are important to prevent transmission failure and ensure smooth gear changes.

Combining these three fluids provides a comprehensive overview of the vehicle’s operational health and helps identify potential issues before they become serious problems.

Other options may mention other fluids like brake fluid or power steering fluid, which are also important but do not form part of the most critical trio for ensuring safe vehicle operation prior to a trip.