What feature allows fonts to be resized and remain clear at any size?

The correct answer is that scalable fonts allow fonts to be resized and remain clear at any size. Scalable fonts are typically vector-based, meaning they are made up of paths defined by mathematical expressions. This allows them to be resized to any dimension without losing quality, ensuring they appear sharp and legible at both small and large sizes.

In contrast, pixel fonts, raster fonts, and fixed-width fonts do not possess the same level of flexibility. Pixel fonts are made up of a fixed grid of pixels, which can become blurry or pixelated when resized beyond their intended size. Raster fonts are also bitmapped and suffer similar limitations; they can only display clearly at their original resolution. Fixed-width fonts, while useful for certain applications such as coding or typewriting, do not inherently have scalable properties, as each character occupies the same horizontal space and they are usually not designed for scaling in the same way scalable fonts are.