Answer:
Serbia
Explanation:
Now before explaining this is kind of an opinionated question and answers could vary from person to person. The reason I believe Serbia is most responsible for the Great War is due to the assasination of Archduke Franz Ferdinand by Gavrilo Princip a Serbian nationalist with ties to the secretive military group known as the Black Hand. It is agreed by most that the beginning of WW1 or The Great War is not only due to this assasination but also due to the alliances being formed pre-war but despite this the actions of Mr. Princip kickstarted one of the bloodiest wars in history that will never be forgotten.
Korea had been required to tribute to China regularly, while Japan was not required to tribute as much.
