What must a driver do when seeing a pedestrian wearing a yellow armband marked with three black dots attempting to cross the street?

Answer: B — Slow down and stop if necessary to allow the pedestrian to cross

When a driver encounters a pedestrian wearing a yellow armband marked with three black dots, it indicates that the individual is "visually impaired" and may need extra assistance to navigate safely. Consequently, the correct action for the driver is to slow down and stop if necessary, allowing the pedestrian the opportunity to cross the street safely. This measure not only aligns with traffic safety laws concerning pedestrians but also demonstrates respect and consideration for individuals with disabilities. Ensuring that there is ample time and space for the pedestrian to cross mitigates the risk of accidents and promotes a safer environment for all road users.