The correct answer to this open question is the following.
Although there are no options attached we can say the following.
Before World War 1 started, why do you think so many people said, “it felt like a powder keg, ready to explode". This meant that the situation was so tense, so risky, that any small detail or incident could have caused the beginning of the warlike actions in the European continent.
One of the main causes of World War I is tied with the Serbian terrorist group, the Black Hand, and was the assassination of Austrian-Hungary Archduke Franz Ferdinand and his wife on June 28, 1914. He and his wife Sophie were in Sarajevo to oversee the Austrian troops stationed there.
During the war, the Allied Powers of France, Great Britain, Russia, Italy, and the US defeated the Central Powers comprised of Germany, Bulgaria, the Austria-Hungary Empire, and the Ottoman Empire.
