Which of the following is a requirement for rear lights during inspection?

The requirement for rear lights during inspection is that they must display a red color. This standard is essential for ensuring visibility and safety on the roads. Red lights indicate to drivers behind a vehicle that it is either braking or stopped, and they help in preventing rear-end collisions.

The functionality of rear lights is not just about illumination but about conveying the correct signals to other road users. A red light is universally recognized as a warning signal, and adhering to this color requirement is critical for the safe operation of vehicles.

The other options, while they touch on related aspects of light functionality, do not encompass the critical color specification that is part of the inspection standards.