What element must be present in order to process a column in a layout template?

In Liferay, processing a column in a layout template requires the invocation of a method that directly handles the processing logic. The method $processor.processColumn() is specifically designed to take a column as input and execute the appropriate processing tasks associated with that column. This method is integral to the system’s ability to generate the final rendered output based on the layout configuration, thus serving as a critical component in the layout rendering workflow.

The other options represent methods that may suggest some interaction with layout columns but do not indicate the actual processing step needed for rendering them. For example, methods that add, define, or create columns pertain to their initial setup or declaration rather than the subsequent processing required to render them in the final output. Therefore, the function responsible for executing the logic tied to a column, ensuring it is processed in the context of the overall layout, is paramount and is effectively captured by $processor.processColumn().