Answer:
It expanded the influence of the United States in the Western Hemisphere
Explanation:
The Monroe Doctrine's importance to the United States was that "It expanded the influence of the United States in the Western Hemisphere."
This is evident in the fact that James Monroe, the former United States President who is 1823, asked the European powers to stay away from the affairs of the countries in the American continents (both South and North America). In turn, this gave the United States to declare itself as the police of the Western Hemisphere.
Hence, the correct answer, in this case, is "It expanded the influence of the United States in the Western Hemisphere."
The correct option is : 
The Event that happened before U.S. Constitution was adopted : -
Harvard College was founded
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