Which of these is a statement of opinion? A.While reforestation may not completely replace traditional technology, it could complement it, allowing factories to use smaller, cheaper equipment. B.Cleaning a short ton (0.9 metric tons) of nitrogen oxide through reforestation cost $2,400 to $4,000, compared with $2,500 to $5,000 using traditional equipment. C.Any pollution-cleansing plan in the U.S. would have to win approval from state and federal officials, who would require it to be quantifiable and enforceable. D.Thirty years is too long to allow a 1,000-acre (405-hectare) forest to do the job of one industrial scrubber in ridding the air of pollutants.

D.Thirty years is too long to allow a 1,000-acre (405-hectare) forest to do the job of one industrial scrubber in ridding the air of pollutants.