How long may a driver remain in the passing lane while traveling at a high rate of speed?

Answer: C — Both a and b above

A driver may remain in the passing lane only as long as necessary to safely pass other vehicles. This means utilizing the passing lane to overtake slower traffic, while ensuring that the maneuver is completed efficiently and without unnecessary delay. The intention behind this guideline is to promote safety and smooth traffic flow, as lingering in the passing lane at high speeds can increase the risk of accidents and lead to frustration for other drivers. Additionally, a driver should remain in the passing lane until the vehicle ahead completes its passing maneuver. This ensures that enough space is provided for the vehicle to re-enter the right lane safely after overtaking. Overall, both elements prioritize safe driving practices and maintain orderly traffic movement. Thus, the correct answer reflects the necessity of adhering to these safe driving guidelines while using the passing lane.