Which of the following is a pure natural carpet fiber?

Wool is recognized as a pure natural carpet fiber because it is derived directly from sheep, making it a 100% natural product. The fiber is known for its durability, elasticity, and remarkable ability to retain warmth, which makes it an excellent choice for carpets. Additionally, wool has natural stain resistance and is environmentally friendly, being biodegradable, which aligns with increasing consumer preference for sustainable materials.

In contrast, the other options—polyester, acrylic, and nylon—are synthetic fibers. They are produced through chemical processes and do not originate from natural sources. While these synthetic fibers can offer various advantages such as durability, affordability, and a wide range of colors, they do not possess the intrinsic qualities and environmental benefits that natural fibers like wool do. Thus, wool stands out as the only pure natural carpet fiber among the choices provided.