Multi-lateral diplomacy is an outcome of modern diplomacy, which came to exist after the Congress of Westphalia and usually functions through conferences. (See below: Conference Diplomacy) An important step towards multilateral diplomacy was the establishment League of Nations following the end of the First World War. What was novel about the League of Nations, especially in terms of diplomacy was that it served as permanent base for multilateral diplomacy which used be carried out through conferences that met for once and for some days only. Another phenomena that pushed the development of multilateral diplomacy was the significant increase in the number of states since 1945. Multilateral diplomacy has both strengths and weaknesses. On the weak side it may bring certain issues to a gridlock by any of the parties if a desired outcome is not reached. This may postpone or even sweep away the possibility of any solution. On the strong side it serves as a ground for cooperation. This cooperation can be directed to problem-solving as well as goal-setting in issues concerning the parties, which at times may include all states as in the case of League of Nations or United Nations. The correct answer is Choice E.