Which syntax is used to set an AUI column to replicate a Bootstrap col-6?

The syntax <aui:col cssClass="col-6"> is correct because it directly utilizes the Bootstrap grid system, which employs specific class names to define the width of columns in a responsive layout. In Bootstrap, the class "col-6" divides the available horizontal space into 12 equal parts, with "col-6" taking up 6 of those parts, representing a half-width column.

By using the cssClass attribute in the AUI tag to specify "col-6", you effectively instruct the system to apply the corresponding Bootstrap styles to that column, ensuring proper alignment and responsiveness in the layout.

Other options, while they reference column settings, do not effectively align with Bootstrap's grid system. The use of width percentages or non-standard class names fails to directly replicate the intended Bootstrap behavior or styling conventions, which is based on predefined classes. Thus, opting for the use of predefined Bootstrap classes through the cssClass attribute is the most straightforward and accurate method for achieving the desired layout in AUI.