How many seats are available on a 737-800?

The Boeing 737-800 is designed to accommodate a maximum of 189 passengers in a high-density configuration. This configuration is commonly used by many low-cost carriers, including Ryanair, to maximize passenger capacity and enhance overall revenue. The 737-800 features a single aisle and a typical two-class configuration that might reduce seating capacity but in a single-class setup, it reaches up to 189 seats.

In contrast, the other options reflect either configurations that are not typical for this aircraft model or exceed its designed seating capacity. For practical operations among low-cost carriers, maximizing seating within the aircraft design ensures the most efficient use of resources and passenger transport, making the correct choice 189 seats.