Which of the following is considered a monochromatic color scheme?

A monochromatic color scheme is characterized by the use of a single color in various shades, tints, and tones. This means that all the colors in the scheme are derived from one base hue, providing a cohesive and harmonious look.

In the context of the provided choices, using red, pink, and maroon constitutes a monochromatic scheme because these colors are all variations of red. Pink is a tint of red (created by adding white), while maroon is a dark shade of red (created by adding black). This combination showcases the versatility of one base color and maintains visual harmony throughout the arrangement.

The other options include multiple different hues, which do not align with the definition of a monochromatic scheme, as they incorporate colors that are not variations of one another. Therefore, the selection of red, pink, and maroon aptly exemplifies the concept of a monochromatic color scheme.