TOEFL Reading: ETS-TOEFL阅读机经 - 459944BI9O7PGFX8L$

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Potash from wood ash was used in manufacturing many industrial products, and it was also used to restore nutrients that had been lost from farm soil. B. The use of potash in the manufacture of a wide range of industrial products meant that farmers could make a good profit by exporting the ashes from the wood they burned. C. Farms suffered when wood ashes were converted into potash instead of being exported to market for profit. D. Potash had many industrial uses, but when wood ashes were for potash, farms suffered from the loss of the nutrients that would have restored to the soil.