Which of the following describes a Lally column?

A Lally column is specifically a cylindrical column made of steel, which is often filled with concrete for added strength and support in building structures. These columns are commonly used in construction for supporting floors and ceilings, making them integral to the structural integrity of buildings. Their design allows them to bear significant loads, which is why they are favored in various construction applications.

The other options do not accurately represent what a Lally column is. The choice describing a hollow plastic pipe does not reflect the material or purpose of a Lally column, which is intended for support, not lightweight applications. A support beam reinforced with steel refers to a different type of structure; while a Lally column can serve as a support, it is characterized by its cylindrical form rather than being a beam. Lastly, a decorative structural element does not apply here, as Lally columns, while sometimes visible, are primarily functional rather than aesthetic.