The correct answer is C) this would provide guidance to farmers along the Mississippi and other US waterways.
The other options of the question were A) "through navigation, commerce, and recreation, the river plays a central role in the lives of millions of Americans." B) "Americans will have to learn how to address and support the ecological needs of this great watershed." D) "the Mississippi River has long been crucial to the development and continuance of the US economy and way of life."
The action that the author of "The Great Mississippi River" calls on readers to take in the final paragraph is "this would provide guidance to farmers along the Mississippi and other US waterways."
The author of the "The Great Mississippi River" shares information about this important and historical river that played prominent roles during the Revolutionary War and the American Civil War. The Mississippi River is a strategic river for the transportation of people and products to different parts of the United States. The river serves many porpuses such as trade, entertainment, and recreation, so people have to take care of it and avoid polluting its waters.