(A) ** *The region along the German-Russian border where Russians and Serbs battled Germans, Austrians, and Turks.
(B) *The region of northern France where the forces of the Allies and the Central Powers battled each other.
EXPLANATIONS BELOW
Concept note-1: -The eastern front encompassed the entire frontier between the Russian Empire and Romania on one side and the Austro-Hungarian Empire, Bulgaria and Germany on the other. It stretched from the Baltic Sea in the north to the Black Sea in the south.
Concept note-2: -The Eastern Front describes the theatre of war to Germany’s east. Most of the fighting on the Eastern Front took place between German, Russian and Austro-Hungarian forces. The frontline ran from the Baltic states to the Black Sea, a distance of more than 1, 000 miles (1, 600 kilometres).