Which pigment would likely remain stable in varying pH levels?

Carotenoids are the pigments that are known for their stability across a broad range of pH levels. These pigments are typically found in a variety of fruits and vegetables, contributing to their bright yellow, orange, and red colors. Carotenoids, because of their chemical stability, do not undergo significant structural changes or degradation in response to varying acidity or alkalinity in the environment.

In contrast, other pigments can be more sensitive to pH changes. For instance, anthocyanins, which are water-soluble pigments responsible for the red, purple, and blue colors in many fruits and flowers, can change color with variations in pH, making them less stable. Pheophytin, a derivative of chlorophyll, can also be affected by changes in pH, leading to a loss of its green color. Flavonoids, while they have some stability, can similarly undergo chemical changes in response to pH fluctuations, affecting their color and solubility.

Thus, carotenoids provide a robust option for stability across varying pH levels, making them the correct choice in this context.