Passage: 'Solar panels convert sunlight directly into electricity using materials called semiconductors. When sunlight strikes the panel, it knocks electrons loose, creating a flow of current. Because sunlight is free and does not produce greenhouse gases during operation, solar energy is considered a clean source of power. One limitation is that panels produce less electricity on cloudy days and none at night, so many systems include batteries to store extra energy.' It can be inferred that solar power is least useful...

Answer and explanation

Correct answer: C. at night without batteries

The text says panels produce none at night.

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