What should a learner's permit holder check before driving?

A learner's permit holder should always prioritize the safety of the vehicle before driving, which includes checking critical safety features such as lights, brakes, and tire pressure. These components are essential for ensuring a vehicle operates safely and is visible to other drivers. Proper function of the brakes is crucial for stopping the vehicle effectively, while the correct tire pressure affects traction and handling. Additionally, working lights are necessary for visibility during night driving or in low-light conditions.

Other options focus on less critical aspects that do not directly contribute to driving safety. Checking only the fuel level does not ensure the vehicle is road-ready. While mirrors and seat adjustments are important for comfort and visibility, they do not encompass the broader safety checks necessary before driving. Lastly, adjusting the radio and air conditioning is more about personal comfort rather than ensuring the vehicle is safe to operate. Therefore, the comprehensive safety check outlined in the correct answer is essential for all drivers, especially those in the early stages of learning to drive.