The Eastern Front of the second world war was a conflict that involved a lot of countries. The battle transpired between the European Axis power and co-belligerent Finland against the Soviet Union, Poland, and other allies.
Option (B) Stalingrad is the correct answer. It is the battle between Germany and its allies against the Soviet Union; this battle was won by the Soviet Army, which made the Germany High command to withdraw their army.
Option (A) the battle of Kursk happened during the second world war this battle involved German and The Soviet forces on the Eastern Front near Kursk in the Soviet Union.
Option (C) Kharkiv was an axis counteroffensive that happens in Kharkiv against the Red Army Ilium.