Solar panel installations have increased dramatically over the past decade. A recent study found that residential solar capacity in the United States grew from 2.5 gigawatts in 2012 to over 25 gigawatts in 2022. Researchers attribute this tenfold increase primarily to declining costs, which have made solar energy affordable for middle-income households.
Which finding, if true, would most directly support the researchers' claim about why solar installations increased?
Government subsidies for solar installation remained constant throughout this period
The average cost per watt of solar panels dropped from 2.77 in 2022
The number of solar panel manufacturers tripled between 2012 and 2022
Public awareness of climate change increased significantly
Correct Answer: B
Choice B is the best answer. The researchers claim that "declining costs" are the primary reason for increased solar adoption. Data showing a dramatic price drop from 2.77 per watt directly supports this claim.
- Context clues: The passage states costs made solar "affordable for middle-income households."
- Evidence evaluation: A 62% reduction in price directly proves declining costs.
- Verify: The price data matches the "declining costs" explanation.
💡 Strategy: Look for data that directly measures the specific claim being made.
Choice A is incorrect because constant subsidies don't explain an increase—if they didn't change, they can't cause change. Choice C is incorrect because more manufacturers might indicate a growing market but doesn't prove cost was the factor. Choice D is incorrect because awareness might contribute but doesn't support the specific claim about costs.