(A) Ireland
(B) Australia
(C) United States
(D) ** Europe
EXPLANATIONS BELOW
Concept note-1: -Britain and its Empire’s entry into the war made this a truly global conflict fought on a geographical scale never seen before. Fighting occurred not only on the Western Front, but in eastern and southeast Europe, Africa and the Middle East.
Concept note-2: -It was fought between two coalitions, the Allies (primarily France, the United Kingdom, Russia, Italy, Japan and the United States) and the Central Powers (led by Germany, Austria-Hungary, and the Ottoman Empire). Fighting occurred throughout Europe, the Middle East, Africa, the Pacific, and parts of Asia.