Answer:
Gold and other precious natural metals; silver and copper.
Explanation:
The correct answer is D. The Spanish-American War resulted from an attempt to enfoce the principles expressed by the Monroe Doctrine.
The Monroe Doctrine, synthesized in the phrase "America for the Americans", was elaborated by John Quincy Adams and attributed to President James Monroe in 1823. It established that any European intervention in America would be seen as an act of aggression that would require intervention of the United States. The doctrine was presented by President Monroe during his sixth State of the Union Address. It was taken with doubts, at first, and then with enthusiasm. It was a decisive moment in the foreign policy of the United States. The doctrine was conceived by its authors, especially John Quincy Adams, as a proclamation by the United States of its opposition to colonialism in response to the threat posed by the monarchical restoration in Europe and the Holy Alliance after the Napoleonic wars.
