TOEFL Listening: TPO-TOEFL阅读TPO - 5G5X3M74TBUJV2U1N$

What can be inferred from paragraph 2 about timber in America before the year 1860? A. Farmers of the American West earned most of their income by selling timber to newly arrived settlers. B. Timber came primarily from farmers who wished to supplement their income. C. Timber was much more expensive before the year 1860 because it was less readily available. D. Timber came primarily from large manufacturing companies in the East.