What should customers ensure before returning a rental vehicle?

Customers should ensure a variety of important factors before returning a rental vehicle to avoid potential issues or additional fees. Ensuring the tank is full is vital because many rental companies have specific policies regarding fuel and returning the vehicle with a full tank can prevent extra fuel charges.

In addition, it is essential for customers to return the vehicle clean both inside and out. This not only maintains the vehicle's condition but also helps avoid cleaning fees that the rental company may impose if the car is returned in a dirty state.

Returning the vehicle at the right time is equally critical. Rental agreements usually specify a return time, and returning the vehicle late can lead to extra charges which can accumulate based on the duration of the delay.

Given that all of these factors contribute significantly to a smooth return process and help customers avoid unexpected costs, it is clear that ensuring that the tank is full, the vehicle is clean, and it is returned on time are all essential actions customers should take before returning the rental vehicle. Therefore, the correct answer encompasses all of these necessary preparations, reflecting the best practice for customers.