While towing, trailers should:

The correct answer emphasizes that trailers should carry no passengers while towing. This guideline is vital for safety and stability. Trailers, even when designed for towing, are not equipped with the necessary safety features or structural integrity to securely accommodate passengers. In the event of sudden braking, sharp turns, or accidents, the lack of proper seating and restraints can lead to severe injuries.

When trailers are solely used for cargo, they can be better balanced and the weight distribution can be optimized, which is crucial for safe towing. Additionally, the driver of the towing vehicle has full responsibility for controlling both the vehicle and the trailer. Any added weight from passengers could interfere with the vehicle's ability to brake effectively and could also compromise the handling of the trailer.

While other options present various aspects of towing, such as parking considerations or cargo load, they do not specifically address the critical safety concerns related to carrying passengers in a towed trailer. This focus on passenger safety is why the chosen answer is the most appropriate recommendation for towing practices.