Which statement describes the impact of Russia's 1917 revolution on WWI?

• A. It caused Russia to extend its participation through 1919.
• B. It led to Russia's exit from WWI through the Treaty of Brest-Litovsk, freeing German troops for the Western Front.
• C. It created a new alliance between Russia and Germany.
• D. It immediately ended hostilities on all fronts.

Answer: (B)

When Russia’s revolution brought a new government to power, it led to Russia pulling out of World War I rather than continuing the fight. The Bolsheviks sought peace with the Central Powers and signed the Treaty of Brest-Litovsk in early 1918, which ended Russia’s participation and ceded territory. With Russia out, Germany could redeploy troops to the Western Front, intensifying pressure on the Allies in that theater and shaping the later stages of the war. The other statements don’t fit because Russia did not stay in the war past 1918, did not form an alliance with Germany, and hostilities did not end everywhere immediately after the revolution.