What does the following passage mainly reveal (paragraphs 8-9)?

Generating sections that don’t need a human-provided fuel supply would be in better shape. Geothermal plants, which are powered by the Earth’s internal heat, can run for some time without human intervention.

According to the maintenance manual for the Svartsengi Island geothermal plant in Iceland, every six months the operators must change the gearbox oil and regrease all electric motors and couplings. Without humans to perform these sorts of maintenance procedures, some plants might run for a few years, but they’d all succumb to corrosion eventually.
Answer choices for the above question

A. Although some power plants don’t require human-provided fuel, they still require human maintenance.

B. All lights would quickly go out if there were no human beings on Earth.

C. All power plants need maintenance.

D. Geothermal plants are the ideal forms of power supply on Earth.