If a driver cannot safely complete their run due to adverse driving conditions, how many additional hours may they be permitted to drive?

The correct answer reflects the standards and regulations surrounding safe driving practices in adverse conditions. When drivers encounter hazardous situations such as severe weather or other unsafe driving conditions, they may not be able to reach their destination in the expected timeframe.

In these situations, the guidelines permit an additional two hours of driving time. This allowance helps ensure that drivers have the flexibility to navigate safely, possibly by waiting for conditions to improve or by taking an alternative route. It emphasizes the importance of safety over strict adherence to schedules, which is critical in promoting responsible driving behavior that prioritizes the well-being of both the driver and others on the road.

The other options do not provide sufficient time to adequately adapt to changing conditions. Approaches that allow no additional time or only a small increment would not adequately support drivers in making informed and cautious decisions during challenging situations.