Iron Production Was Transformed by Abraham Darby's Discovery That

Iron production was transformed by Abraham Darby's discovery that

A) machines could do the work of hammering iron better than humans could.
B) mills operated with hydroelectric power produced stronger iron.
C) coke could be used in place of charcoal in the smelting process.
D) taconite was a more valuable byproduct than the iron itself.
E) people worked more efficiently if they were paid higher wages.