If I had a device with a screen width of 800px, which column class prefix would be used?

The choice of the column class prefix for a device with a screen width of 800px falls under the medium breakpoint category in the Bootstrap grid system. In Bootstrap, the grid system is designed to respond to different screen sizes, which are categorized into specific breakpoints.

For Bootstrap versions 3 and 4, the breakpoints are defined as follows:

• Extra-small devices, typically mobile phones (less than 576px) are denoted by the "col-xs-*" prefix.

• Small devices, like larger phones and small tablets (576px to 767px), are denoted by the "col-sm-*" prefix.

• Medium devices, such as tablets and small laptops (768px to 991px), use the "col-md-*" prefix.

• Large devices, like desktops (992px and above), are referred to with the "col-lg-*" prefix.

Since an 800px screen width is characteristic of a medium device, the prefix "col-md-*" is the appropriate choice. This ensures that the layout adjusts correctly for users on medium-sized screens, providing a responsive design that maintains usability and visual coherence across varying devices.