What is a CNG installation that dispenses CNG into fuel supply cylinders installed on vehicles called?

The correct answer identifies a specific type of facility dedicated to supplying compressed natural gas into the storage containers of vehicles. This term reflects a focus on the operational aspect of the equipment and the process involved in providing fuel. The installation not only refers to the physical infrastructure but also emphasizes the act of dispensing the fuel.

A "filling station" typically encompasses broader functions, including multiple types of fuel and may not exclusively refer to CNG. "Fueling installation" is a more generic term that could apply to any type of fuel delivery system without specifically highlighting the dispensing aspect. Meanwhile, a "service station" usually implies a facility where maintenance and repairs are also offered alongside fuel, not solely focused on the dispensing of CNG.

By understanding these distinctions, one can appreciate why "dispensing installation" is the most precise term for a system designed specifically for dispensing CNG into vehicle supply cylinders.