What is the smallest device that will display these columns side by side?

The smallest device that will display the specified columns side by side is a tablet. This is because tablets typically have a screen size that allows for greater real estate compared to a smartphone, making it possible to show multiple columns effectively without requiring the user to zoom or scroll excessively.

Smartphones, while portable, usually have smaller screens that may not accommodate multiple columns side by side in a way that is user-friendly. Desktops certainly support this layout due to their larger screens, but they are not the smallest device in the context of the choices provided. Smartwatches, having very small screens, would struggle to display even a single column of information clearly, thus making them unsuitable for a side-by-side column layout.

In summary, a tablet strikes the right balance of size and usability for displaying multiple columns side by side effectively, which is why it is the correct choice.