A(n) _________ is comprised of an abundant supply of nutrients for mold growth.

The correct choice is that an abundant supply of nutrients for mold growth is found in "material." Mold requires organic matter, such as wood, drywall, and fabric, which are common materials found in many environments. These materials provide the organic compounds that serve as food for mold spores, enabling them to thrive.

While a building may house various materials that could foster mold growth, it does not itself serve as the nutrient source. Similarly, a room can contain multiple surfaces and materials, but it lacks the specificity needed to define where the nutrients for mold are present. Therefore, identifying "material" directly connects to the presence of nutrients essential for mold growth, making it the most accurate choice.