According to the passage, iron was NOT used for beams, columns, and girders prior to the early eighteenth century because _____. A. all available iron was needed for other purposes B. limit
According to the passage, iron was NOT used for beams, columns, and girders prior to the early eighteenth century because _____.
A. all available iron was needed for other purposes
B. limited mining capability made iron too expensive
C. iron was considered too valuable for use in public buildings
D. the use of charcoal for refining ore produced poor quality iron