What should you do when following drivers who cannot see your vehicle?

Answer: A — Increase your speed

When following drivers who cannot see your vehicle, it is important to increase your speed. By doing so, you can pass them quicker, reducing the time spent in their blind spot and decreasing the chance of an accident caused by them not seeing you. It is crucial to always take proactive measures to ensure your safety on the road. Options B, C, and D are not the best actions to take in this situation. Reducing your speed and falling back may not help the driver see you any better, moving into another lane might not be feasible or necessary, and flashing your headlights can be confusing or even dangerous for other drivers.