Which could be mistaken for an insect infestation?

Choosing "All of these" as the answer is correct because each of the listed items can potentially mimic signs typically associated with an insect infestation.

Fiberglass insulation fibers can sometimes resemble insect bodies or debris when they accumulate, especially in corners or along baseboards. Homeowners may mistakenly interpret this build-up as evidence of insect activity.

Static electricity can lead to the attraction of dust and small debris that might also resemble insects. This can create an illusion of an infestation, particularly if small particles are seen moving or collecting in specific areas.

Very dry air conditions can cause environmental changes that may lead to increased sensitivity to things like dust and other particles, which might lead individuals to suspect an insect presence when the evidence is actually environmental rather than biological.

In essence, all of these factors—fiberglass fibers, static electricity, and dry air—can create scenarios where individuals might misinterpret benign materials or phenomena as signs of pests, making "All of these" the most comprehensive and accurate response.