Which of the following ants is categorized as a house-nesting ant?

The carpenter ant is categorized as a house-nesting ant due to its preference for nesting in wood, especially in structures like homes. These ants are known to excavate wood to create their nests, making them particularly relevant to structural pest control. Unlike other ant species that might nest in soil or outdoor environments, carpenter ants are often found in damp or decaying wood, which is common in many residential settings.

In contrast, the Argentine ant is known for forming large colonies and primarily nests in soil, though it can invade homes. The harvest ant typically builds nests in dry, sandy soils in open areas, not within structures. The southern fire ant is more likely to establish colonies in outdoor environments and does not typically nest within homes. This distinction highlights why the carpenter ant is the correct answer for a species that commonly nests inside human dwellings.