What must a driver do to reduce glare for oncoming traffic?

Answer: C — Dim headlights

To reduce glare for oncoming traffic, a driver should dim their headlights. High beam headlights are designed for use in low-light conditions where there is little to no oncoming traffic, as they provide maximum illumination of the roadway. However, using high beams when approaching vehicles can create significant glare that impairs the vision of drivers in those vehicles. Dimming the headlights or switching to low beams minimizes glare, which not only protects the vision of oncoming drivers but also increases overall safety on the road. This consideration is essential in ensuring that all drivers can see clearly without distraction or impairment caused by excessive light. Changing lanes frequently does not address the issue of glare—it may disrupt traffic flow and create a hazardous driving environment instead. Similarly, speeding up does not mitigate glare and can lead to dangerous driving behaviors, making it a poor strategy. Thus, dimming the headlights is the appropriate action to take in this context.