Which of the following best describes primary colors?

Primary colors refer to a set of colors that cannot be created by mixing other colors together. In the context of color theory, primary colors serve as the foundation for creating all other colors. Specifically, in traditional color theory, the primary colors are red, blue, and yellow. When combined in various ways, these colors can produce secondary colors (such as green, orange, and violet) and eventually a vast spectrum of hues.

Understanding this concept is crucial for nail technicians, as it allows them to mix colors effectively for nail art and design, ensuring they achieve the desired shades and effects. The other options describe different color properties or relationships but do not accurately define what primary colors are. For instance, some choices refer to the mixing of colors or their positioning on the color wheel, which is not relevant to the definition of primary colors themselves.