What is the purpose of using chop blocks during fuel delivery?

Using chop blocks during fuel delivery serves the important function of securing the truck in place. This practice enhances safety by preventing any movement of the delivery vehicle during the unloading of fuel. When fuel is being delivered, the truck must remain stable to avoid any risk of accidents, spillage, or damage to the fuel lines and storage facilities. By placing chop blocks securely behind the truck's wheels, it helps to immobilize the vehicle on inclines or uneven surfaces, ensuring that the delivery process can be conducted safely and efficiently.

While the other options involve necessary tasks around fuel delivery, they do not relate directly to the specific function of chop blocks. Measuring fuel levels, connecting fuel lines, and cleaning the site after delivery are all important processes, but they are not the primary purpose of using chop blocks during the delivery operation.