Which of the following colors can be described as a tertiary color?

A tertiary color is formed by mixing a primary color with a secondary color. In the traditional color wheel, the primary colors are red, blue, and yellow, while the secondary colors are green, orange, and purple. When you mix a primary color with a secondary color, you create a tertiary color.

Red-orange, specifically, is created by mixing red (a primary color) with orange (a secondary color). This blend results in a color that lies between red and orange on the color wheel, making red-orange a perfect example of a tertiary color.

In contrast, green, yellow, and blue are primary or secondary colors and do not result from mixing a primary with a secondary. Therefore, they cannot be classified as tertiary colors.