Which of the following is essential to adjust while driving in the dark?

Adjusting the instrument lights while driving in the dark is crucial for maintaining visibility and ensuring that you can easily read the dashboard gauges and controls. When driving at night, ambient light is significantly reduced, which can make it difficult to see the instruments necessary for safe driving, such as speedometer, fuel gauge, and warning lights. Properly illuminated instruments help you monitor the vehicle's performance and respond to any issues immediately.

While navigation systems, ventilation systems, and radio volume may also require adjustments, they do not have the same direct impact on immediate driving safety in low-light conditions. Ensuring that instrument lights are at an appropriate level enhances overall situational awareness and contributes to safer vehicle operation at night.