What was the outcome of the 1914 Battle of Tannenberg on the eastern front?

a. Russia was decisively victorious, capturing more than 50,000 German troops and halting their advance.
b. The battle caused Russia to seek a peace treaty to end its conflict with Germany.
c. the battle resulted in a stalemate as both Russian and German armies suffered heavy losses.
d. Russia suffered almost 80,000 casualties and 90,000 prisoners of war as compared to Germany’s 15,000 casualties.