According to the passage, what was a major result of railroad building in the nineteenth century? A．The majority of wealth became concentrated in a few powerful nations. B．Competition increased between private and state-owned companies. C．There was an increase in the demand for an educated workforce. D．Large parts of the world became populated and economically developed.
A.The B. B．Competition C. C．There D. D．Large E.
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D 解析：A major result of railroad building in the nineteen......