Which type of columns can be placed inside architectural columns?

In Revit and architectural design, structural columns are specifically designed to support loads and can be placed within architectural columns because they serve different purposes. Architectural columns are primarily used for aesthetic design and can encapsulate structural columns within them to enhance the visual appeal of a space while still providing the necessary structural integrity.

Structural columns can be hidden within architectural columns to achieve a cleaner and more cohesive architectural design. This ability to combine the two types allows architects and designers to maintain both functionality and form in their designs, ensuring that the overall appearance remains cohesive while still adhering to engineering requirements.

The other options do not fit the context. Architectural columns cannot contain more architectural columns as they serve different roles, and while load-bearing columns might be structural elements, they are not inherently part of the architectural design concept in the same way that structural columns are utilized. Thus, structural columns are the only type that can be efficiently placed within architectural columns without compromising design intent or functionality.