Which is the most likely location of a curtain wall?

A curtain wall is a non-structural outer covering of a building that is typically made of lightweight materials and is used primarily in high-rise structures. Its main function is to shield the interior environments from the elements, such as wind, rain, and temperature variations, without adding significant weight to the overall structure.

In the context of being located on the exterior of a high-rise, curtain walls are specifically designed to be part of the building's facade. They often incorporate glass, metal, and other modern materials to create aesthetically pleasing and functional exteriors. This makes the option of the exterior of a high-rise the most appropriate and likely location for a curtain wall.

The other possibilities, while they may involve varying building features, do not align with the typical functionality or installation of curtain walls. Industrial facilities may prioritize fire-resistant materials and structural integrity rather than aesthetic and lightweight options. Ceiling areas can also contain structural elements rather than non-load-bearing features like curtain walls. Lastly, open stairwells typically require different types of construction to ensure safety regulations are met, rather than incorporating a system designed for exterior use.