Which device will display a Bootstrap row in stacked columns when using a specific column class?

The device that will display a Bootstrap row in stacked columns when using a specific column class is a smartphone. This behavior is part of Bootstrap's responsive design approach, which uses a grid system that adapts to different screen sizes.

When you use column classes in Bootstrap, they are designed to create a flexible layout that stacks columns vertically on smaller screens such as smartphones. For instance, if you apply column classes that are set for small devices (like .col-sm-*), the columns may experience a stacked layout due to limited screen width, allowing for better readability and usability on these smaller displays.

This stacking effect is intended for smaller devices, ensuring that users can navigate the content easily without having to zoom or scroll horizontally, which enhances the overall user experience. In contrast, larger devices such as tablets, desktops, and large screens typically allow for multiple columns to be displayed side by side, utilizing the available horizontal space more effectively.