Final answer:
The best practice when driving behind a large truck on a freeway is to drive at a slower speed than the truck to maintain a safe following distance, improve visibility, and ensure enough reaction time.
Step-by-step explanation:
When driving on the freeway behind a large truck, you should maintain a safe following distance, which usually means driving at a slower speed than the truck to ensure enough reaction time and stopping distance in case the truck brakes suddenly. Additionally, driving more slowly than the truck improves your visibility and allows you to anticipate road hazards. Therefore, the answer is option 1) At a slower speed than the truck.