Answer:
Option C, the closing of the western frontier, is the right answer.
Explanation:
An argument that claimed that American democracy was established by the American frontier came to be known as the Frontier Thesis. This argument was presented by historian Frederick Jackson Turner in the year 1893. He argued that the primary result of the American frontier was American democracy along with a lower interest in high culture, violence and egalitarianism.
Answer is in the file below
tinyurl.com/wpazsebu
Austria used it as a flimsy excuse to start a war with Serbia, which it had been wanting to do anyway.
