Answer: C) The Telephone
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Explanation:
The first phone call ever made was on March 10, 1876. This was more than a decade after the Civil War ended.
Meanwhile, the telegraph was heavily used throughout the Civil War, as well as Railroads and steam engines. The Erie Canal was completed in 1825, which was well before the Civil War started (April 12, 1861). This allows us to rule out choices A, B and D.
