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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. Private investment in railroads began in the 1850s following the dramatic expansion of the railroad network, which had been financed by local governments. B. Railroads' relations with local governments became strained in the 1850s, when railroads turned to private investors for financing to expand their capacity. C. Local governments' limited capacity to finance railroad expansion was a long-standing problem that railroads solved in the 1850s by turning toward private investment. D. When local governments could not adequately finance the railroads' dramatic expansion in the 1850s, private investment became increasingly important.