This was the early-19th century announcement that the american continents were not subjects for future colonization by any european country.

Monroe Doctrine was the early-19th century announcement that the American continents were not subjects for future colonization by any European country.

Monroe Doctrine

Explanation:

The theory that sought to prevent any part of the American continent from being colonized by European countries in the early 19th century is known as Doctrine Monroe. Its promoter was James Monroe, the fifth president of the United States of America, but its author was Jhon Quincy Adams. With it, Monroe tried to prevent the interference of European states in the Americas, just at the moment when Spain and Portugal lost their colonies in that space. Taking advantage of this emptiness of Spanish and Portugal power in its former colonies, England, France, Holland and, other European countries, they sought to take advantage of the situation to expand imperially in the Americas. The phrase "America for the Americans" comes to summarize this policy, which was systematically developed throughout the continent from the 40s of the 19th century.

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation:

answer; i do believe its (wife); good luck