Which of the following must be checked during a pre-trip inspection?

Answer: C — Tires, brakes, lights, and emergency equipment

During a pre-trip inspection, it is essential to check tires, brakes, lights, and emergency equipment because these components are crucial for the safe operation of the school bus. Tires need to be inspected for proper inflation and tread depth to ensure optimal traction and handling. Brakes are vital for stopping safely; any issues with them could lead to severe accidents. Checking lights ensures that all signaling devices are functioning correctly, which is important for visibility and communication with other road users. Emergency equipment, such as fire extinguishers and first aid kits, needs to be present and properly stocked in case of an emergency. The emphasis on this comprehensive checklist during a pre-trip inspection is part of the broader safety protocols that help prevent accidents and ensure passenger safety. Other choices do not cover the full spectrum of necessary checks, making option C the correct choice.