GMAT-9-37请教求解思路

sv2000

Because mining and refining nickel is costly, researchers have developed an alternative method for extracting nickel using Streptanthus polygaloides, a plant that absorbs and stores nickel form the soil as it grows.  The researchers incinerated a crop of Streptanthus they grew in nickel-rich soil.  By chemically extracting nickel from the ash, they produced 100 pounds of nickel per acre of land at a total cost per pound slightly above that of current mining. Which of the following, if true, most strongly supports the conclusion that the use of Streptanthus to extract nickel will be commercially adopted?

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yangsh

b

deanjiang

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