Answer:
The German Empire
Step-by-step explanation:
After the assassination of Franz Ferdinand the Austro-Hungarian Empire declared war on Serbia and thus inadvertently found themselves at war with a variety of other major superpowers. Such a predicament called the help of the Austro-Hungarian ally, Germany or, as they were referred to in 1914, the German Empire due to the Austrian-German alliance that had been created to preserve the two nations close diplomatic relations.