B. Isolationism is a foreign policy approach favoring involvement in foreign affairs.
Step-by-step explanation:
All of these are true, except "isolationism is a foreign policy approach favoring involvement in foreign affairs." This is false. Isolationism is actually the opposite of favoring involvement in foreign affairs, it is wanting to stay out of foreign affairs completely.
After World War I, many Americans were isolationists. This meant that they did not want to become involved in foreign affairs and only wanted to worry about themselves. World War I contributed to this because of how gruesome and terrible the war was, people did not want a repeat of this so they would rather just stay out of foreign affairs.
The reason why the United States Congress did not approve of President Woodrow Wilson's "League of Nations" was because they believed it would draw the country into unwanted affairs. As part of Wilson's "Fourteen Points," he pushed for the League of Nations to be created. The United States never joined the League, which contributed to how weak it was.
Isolationism also contributed to World War II. Since the United States wanted nothing to do with foreign problems, this made it easy for an authoritarian rule to take over. Isolationism also worsened the Great Depression and caused World War II to be worse in the future, as the United States let foreign problems be for too long by the time they joined.