Final answer:
A sign of carpenter ant infestation would be all of the options listed: ant borings in the basement, dark closet, and under a porch, as these pests create nests in moist and damaged wood areas.
Step-by-step explanation:
A sign that carpenter ants have infested would be D. All of the above. Carpenter ants are known to create nests in areas where wood is moist and damaged. Therefore, their borings can be found in multiple locations, including the basement, dark closets, and under porches. These ants excavate wood to create smooth tunnels inside the wood as they expand their nest. The presence of fine wood shavings mixed with parts of dead ants or fecal pellets, called frass, is a common indicator of an infestation. It is also possible to hear a rustling sound from the ant activity if the infestation is extensive.