Answer:
a timber company that replants harvested areas within three years
Step-by-step explanation:
Given that sustainability of materials or resources is a term that describes the maintenance of such material or prevention of overexploitation of such resources to maintain its supply.
Hence, in this case, the correct answer is "a timber company that replants harvested areas within three years, " simply because the replanting of the harvested trees, will make the resources readily available in the future, thereby maintaining its steady supply.