During the Great War, other central power nations that joined the Triple Alliance were the Ottoman Empire, and Bulgaria. In the case of your question, the answer will be Bulgaria.
Number 1.is the correct answer I attached a screenshot that explains about it I hope you can see it!
South Korea north and China
Answer: the 1930s
Explanation: The USA watched carefully the rise of fascism in Europe and Japanese expansion in Asia, but did not intervene, There was a strong isolationist lobby and many had sympathy with both Hitler and Mussolini who they saw as leaders who were putting to rights, the problems of their countries, and were also important bulwarks against communism.
It took the Japanese attack on Pearl Harbour to bring the USA into the war and even then there was no guarantee they would have become directly involved in the conflict in Europe. It was Hitler who declare war on the USA in support of his Japanese Axis allies.