(A) ** Eastern front
(B) Western front
(C) Northern front
(D) Southern front
EXPLANATIONS BELOW
Concept note-1: -On the Eastern Front, Germany and other members of the Central Powers, such as Austria-Hungary and Bulgaria, fought against Russia and Romania of the Allied and Associated Powers.
Concept note-2: -The Battle of Stalingrad (23 August 1942 – 2 February 1943) was a major battle on the Eastern Front of World War II where Nazi Germany and its allies unsuccessfully fought the Soviet Union for control of the city of Stalingrad (later renamed Volgograd) in Southern Russia.
Concept note-3: -The Eastern Front is best known for the multi-year Siege of Leningrad and the bloody Battle of Stalingrad, but it was also the site of the largest armored confrontation of all time.