Answer:
The right answer is:
Russia withdrew its troops from the war, allowing Germany to focus on the Western Front.
Explanation:
In early 1918, the new Bolshevik government signed the Treaty of Brest-Litovsk with Germany. It agreed to a huge loss of territory and population. The peace treaty, though highly negative for Russia, allowed the Bolsheviks to stop the war and focus on domestic issues; WWI had caused chaos in Russia, which had performed very badly in the conflict.
