Which of the following is considered a primary color?

In color theory, primary colors are defined as the foundational colors that can be combined to create a broad spectrum of other colors. In the traditional color wheel, red is classified as one of the three primary colors, alongside blue and yellow. These colors cannot be created by mixing other colors together; instead, they serve as the basic building blocks for other hues. For instance, mixing red with yellow results in orange, while mixing red with blue produces purple.

The other options listed, such as green, orange, and purple, are secondary or tertiary colors formed by blending primary colors. Green is made by combining blue and yellow, while orange is derived from mixing red and yellow, and purple results from the mixture of red and blue. Recognizing red as a primary color is essential for understanding color mixing and the creation of various shades in art and design.