Why are some Audi A3 models more fuel efficient than others?

I am trying to understand why some Audi A3 models have higher fuel efficiency ratings than others. Is it due to certain engine configurations, technology, or something else?

Audi A3 e-tron models have higher fuel efficiency ratings due to their hybrid powertrain that combines a gasoline engine with an electric motor. This allows for the car to operate on pure electricity for shorter distances, reducing overall fuel consumption.

The Audi A3 TDI models also have higher fuel efficiency ratings thanks to their diesel engine, which typically delivers better fuel economy than gasoline engines. However, it is important to note that these models may have higher upfront costs and require regular maintenance to maintain their efficiency.

The overall fuel efficiency of an Audi A3 model also depends on factors such as aerodynamics, weight, and tire type. Models with less drag and lighter weight can achieve higher fuel efficiency, and low rolling resistance tires can also contribute to better gas mileage.