Final answer:
The least likely point of entry for subterranean termites in a house is the wainscot (option A) , as it is above ground level and not in direct contact with the soil, unlike areas around plumbing entrances, expansion joints, and cracks in the slab.
Step-by-step explanation:
The point that is least likely to serve as an entry for subterranean termites in a house is A. Wainscot. Subterranean termites typically enter structures near the ground level, since they originate from soil. They commonly exploit vulnerabilities such as B. Around plumbing entrances in slab, C. Expansion joints, or D. Crack in slab, where soil is in direct contact with wooden structures or where there are passages created by plumbing and other utilities, or concrete joints.
A wainscot, which is a paneling applied to the lower part of an interior wall, is above ground level and, therefore, not typically in direct contact with the soil. This makes it the least likely point of entry compared to other options that are more accessible from the soil where termites thrive. However, it is important to note that if there is significant moisture, damage, or if the wainscot is in contact with the ground, it could potentially become a point of entry.