The correct answer is - It enabled the Soviets to push the eastern front toward Germany.
After the Soviets won over the Germans in Stalingrad, the roles had switched, Germany was the one who was under attack, unlike previously when it was always the one that attacks the others.
The Soviets were gradually pushing the eastern front towards Germany, and the Germans were not very good at stopping them, first, because they were exhausted military and with supplies, and second, because the German army was built for attack, not for defense.
The Allies attacked Germany from the western side as well, and Germany found itself in the middle between multiple countries attacking it, so it eventually lost the war.
