Answer:
(3)the United States has not become a member
Explanation:
The league of Nations was part of the treaty of Versailles negotiations, and it stated that the several nations would form a league fo nation that would protect the world from future threats from nations that would want to conquer or invade other nations, but the senate of the united states rejected the treaty because it might need the american army to fight future wars all over the world. The american contribution was vital to the League of nations and its prosperity, and that why you can see the american cornerstone not put into the bridge that would strenghten the league of nations.