World War I was started in $$1914$$ between two alliance, the Triple Entente (Britain, France, Russia) and the Central Powers (Germany, Austro-Hungarian Empire and Ottoman Empire). Which event triggered the war?
The German conquest of Poland.
The assassination of Archduke Franz Ferdinand of Austria Hungary.
The attack on Gallipoli by the Australian and new Zealand Army Corps (ANZAC).
The bombing of Pearl harbour in the US.