What are the most common engine sizes available for the Audi A2 and how do they affect fuel efficiency?

I'm interested in purchasing an Audi A2 and I've heard that engine size can greatly impact fuel efficiency. I want to know what engine size options are available for the A2 and how they compare in terms of fuel efficiency.

The most common engine sizes for the Audi A2 are 1.4L, 1.6L, and 1.9L. The smaller the engine, the better the fuel efficiency as it requires less fuel to power the vehicle. However, the trade-off is less overall power and acceleration.