What are the restrictions on the protrusion of fuel supply containers?

The correct choice emphasizes that no parts of fuel supply containers should extend beyond the sides or top of the vehicle. This requirement is critical for ensuring safety on the road. When fuel containers are properly contained within the dimensions of the vehicle, it reduces the risk of accidents, such as collisions with other vehicles or fixed objects. Additionally, maintaining the profile of the vehicle at an appropriate level helps improve aerodynamics and stability during operation, which is particularly important for trucks that are carrying hazardous materials like compressed natural gas. Ensuring that containers do not extend beyond the vehicle’s boundaries also complies with regulations designed to promote safety and protect both the driver and the public.