The telegraph was the key invention that transformed communication during the Industrial Revolution by allowing instant message transmission over long distances. This innovation greatly impacted society and economics, making communication faster and more efficient than previous methods like written letters or postal services. Therefore, the correct answer is C. telegraph.
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The telegraph was the key invention that transformed communication during the Industrial Revolution by allowing instant transmission of messages over long distances. It enabled faster information exchange across various sectors, significantly impacting society and economics. Other methods, like written letters and the post office, were slower and less efficient in comparison. ;