Answer:
Step-by-step explanation:
MOST TO BLAME
AUSTRIA-HUNGARY
Serbia
Germany
Russia
France
Britain
Italy
LEAST TO BLAME
================================================================= Austria-Hungary is most to blame for the war despite Serbia having an involvement in the assassination of Franz Ferdinand as Austria-Hungary had sent Serbia a 10 point ultimatum which was designed to make sure that these demands were impossible for Serbia.
Italy is least to blame as Italy did not throw more wood into the burning flame which are alliances as alliances between countries was the main reason which it escalated in the end. Italy did join in the end in the Entente's side as they were promised large swathes of Austria-Hungarian land. But they at least did not throw more wood into a burning fire which could have caused more problems.
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! HOPE I HELPED !