What fluid levels must be checked in the engine compartment during pre-trip inspections?

In a pre-trip inspection, it is essential to check various fluid levels in the engine compartment to ensure the vehicle operates safely and efficiently. The correct choice includes oil, coolant, windshield washer fluid, and brake fluid.

Oil is a critical component for engine lubrication, and checking its level prevents engine wear and damage due to insufficient lubrication. Coolant level checks are crucial to avoid engine overheating, ensuring the vehicle runs at an optimal temperature. Windshield washer fluid is important for maintaining visibility, especially in adverse weather conditions, and ensuring that the wipers can effectively clear the windshield. Lastly, brake fluid is vital for maintaining effective braking performance—insufficient brake fluid can lead to brake failure.

Verifying all these fluid levels helps to ensure the vehicle's reliability and safety before hitting the road. Neglecting any of these checks can lead to mechanical failures or safety hazards during operation. Hence, thorough checks of all these fluids are standard practice in pre-trip inspections.