The best and most correct answer among the choices provided by your question is the third choice or letter C. The Louisiana Purchase is an example of how the political geography of North America was changed by the Napoleonic Wars.
The Americans thought that Napoleon might withdraw the offer at any time, preventing the United States from acquiring New Orleans, so they agreed and signed the Louisiana Purchase Treaty on April 30, 1803. On July 4, 1803, the treaty reached Washington, D.C..
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