The correct answer to this question is C) position 3.
As Carl Becker [1] pointed out during the rise of European fascism after World War I [2], for democracy to prosper, it needs "a certain measure of economic security" [3]. The citation should be inserted in position 3.
When doing research, you basically have three common ways to cite your sources. The first one is MLA, which stands for Modern Language Association, often used by humanities subjects. The next one is APA, which stands for the American Psychological Association, often used in areas of psychology, science, and education. The third one is the Chicago style, commonly used when researching History, Fine Arts, and Business.