Why is the fuel consumption of the Audi A6 so efficient?

I've been considering purchasing an Audi A6, but I'm curious about its fuel efficiency. Can someone explain why it is considered an efficient car?

The Audi A6 is equipped with a 48-volt mild hybrid system, which helps to reduce fuel consumption by shutting off the engine when it's not needed. It also has an optimized aerodynamic design to decrease drag and improve fuel efficiency.

The A6 also has a start-stop system, which automatically turns off the engine when the car is stopped, saving fuel. Additionally, it has a regenerative braking system, which captures energy while braking and stores it to power the vehicle's electronics.

Another contributing factor to the A6's efficiency is its lightweight construction, thanks to the use of aluminum in its body and chassis. This helps to reduce overall weight and improve fuel economy.