Why did Austria-Hungary declare war on Serbia? How did the political climate of Europe at the time help contribute to the escalation of this conflict into a "Great War"?

Great War.

Explanation:

Austria-Hungary declares war on Serbia after the assassination of Ferdinand and his wife.

The assassination is generally thought to be one of the major events that led to the war in Europe. The Austria-Hungary government blamed the Serbians, believing to have helped the Bosnian terrorists in killing. Serbia supported by the Russians, and the Austria- Hungary government along with the Germans declared war on Serbia. All this led to the beginning of World War I in Europe that extended and formed two sides, the Central Powers and Allies.

all of the choices are correct

it was a act of seld fesnse more over it was a peace treaty between the fogein contunries.