Reread paragraphs 29-33 of the article. Then answer the multiple-choice questions that follow. From “The Last Human Light” by Randall Munroe
Solar power

29 Emergency call boxes, often found along the side of the road in remote locations, are frequently solar-powered. They usually have lights on them, which provide illumination every night.

30 Like wind turbines, they’re hard to service, so they’re built to last for a long time. As long as they’re kept free of dust and debris, solar panels will generally last as long as the electronics connected to them.

31 A solar panel’s wires and circuits will eventually succumb to corrosion, but solar panels in a dry place, with well-built electronics, could easily continue providing power for a century if they’re kept free of dust by occasional breezes or rain on the exposed panels.

32 If we follow a strict definition of lighting, solar-powered lights in remote locations could conceivably be the last surviving human light source.

33 But there’s another contender, and it’s a weird one.

The author’s purpose in opening this section by introducing the topic of emergency call boxes is probably to:

Answer choices for the above question

A. Explain the process by which solar panels work.

B. Inform readers that lighted call boxes are often located in areas where there are few humans.

C. Describe why solar panels can last for so long without human intervention.

D. Tell readers how long a light powered by a solar panel would probably last.