Final answer:
Argentine ants typically enter structures through cracks in the slab or foundation, exploiting small openings in a building's exterior to form an infestation. The correct option is A. Through cracks in the slab (or foundation)
Step-by-step explanation:
Argentine ants most likely enter a structure through cracks in the slab (or foundation). These tiny insects are excellent at finding the smallest openings in a building's exterior and can easily exploit any weaknesses to gain entry.
Typically, one might observe a colony of ants forming a line up a wall, which on closer inspection reveals thousands of individual ants, each contributing to the formation of the infesting black line.
While doorways are obvious entry points, ants are likely to use less conspicuous methods to invade a structure. They might enter through wall voids and drywall, particularly if there are gaps or cracks, but they can also find their way into wooden structures, although this is not their most common point of entry.
Proper sealing and maintenance of the building's foundation are essential in preventing an ant infestation. The correct option is A. Through cracks in the slab (or foundation)